International Experiences with Vaginal Lengthening Treatment Among Individuals with Müllerian Agenesis: A Mixed-Methods Study.

STUDY OBJECTIVE: To understand variations and experiences of vaginal lengthening internationally in individuals with congenital underdevelopment of the uterus, cervix, and upper vagina or Müllerian agenesis METHODS: In this study, we used a cross-sectional mixed-methods design incorporating quantitative and qualitative questionnaires. Adults with Müllerian agenesis completed questionnaires with quantitative and open-ended qualitative questions about their vaginal lengthening experiences. Data were analyzed using descriptive statistics and inductive thematic analysis. RESULTS: Of 616 respondents meeting inclusion criteria (representing 40 countries), 46% (n = 284) reported no vaginal lengthening intervention. Vaginal lengthening was commonly reported by participants from North America and Europe (59%) and less commonly by participants from Africa, Asia, and South America (16%). Of those who had undergone vaginal lengthening, 72% reported dilator use, 34% coital dilation, and 39% surgery. Four major themes were identified in response to the open-ended vaginal lengthening experience question: (1) difficult physical symptoms, (2) practical and psychosocial challenges, (3) intimate relationships and sexual satisfaction, and (4) impact of experiences with healthcare providers. CONCLUSION: This study highlights vaginal lengthening practices internationally and shared themes related to significant challenges and positive experiences. The findings show room for improvement in the counseling and care surrounding vaginal lengthening. Future research should investigate factors that influence decision-making about vaginal lengthening and work toward international consensus on best care practices in Müllerian agenesis.

Prevalence of urinary, prolapse, and bowel symptoms in Mayer-Rokitansky-Küster-Hauser syndrome.

BACKGROUND: Müllerian agenesis, or Mayer-Rokitansky-Küster-Hauser syndrome, occurs in 1 in 4500 to 5000 individuals assigned female sex at birth. Pelvic floor symptoms among individuals with Mayer-Rokitansky-Küster-Hauser syndrome have not been well studied, and it is unknown how vaginal lengthening treatments affect these symptoms. OBJECTIVE: This study aimed to assess urinary, prolapse, and bowel symptoms in individuals with Mayer-Rokitansky-Küster-Hauser syndrome and to determine whether symptoms vary by vaginal lengthening treatment. STUDY DESIGN: We conducted a cross-sectional study in 2019 using an online survey distributed by the Beautiful You MRKH Foundation via social media to individuals with Mayer-Rokitansky-Küster-Hauser syndrome. Demographics, age at and timing of diagnosis, information about vaginal lengthening treatment, urinary symptoms (Michigan Incontinence Symptom Index), prolapse symptoms (Pelvic Organ Prolapse Distress Inventory short-form version), and bowel symptoms (Bristol Stool Form Scale) were obtained. The inclusion criteria included self-reported diagnosis of müllerian agenesis and female sex. Respondents with a history of renal transplant or dialysis, completion of <85% of the survey, and non-English survey responses were excluded. Descriptive analyses were used to describe the sample population. Logistic regression, Kruskal-Wallis, and Fisher exact tests were used to compare the prevalence of pelvic floor symptoms and vaginal lengthening treatments. Associations between age and genitourinary symptoms were investigated with Spearman correlations. RESULTS: Of 808 respondents, 615 met the inclusion criteria, representing 40 countries. 81% of respondents identified as white. The median age of the participants was 29 years (interquartile range, 24-36), with a median age at diagnosis of 16 years (interquartile range, 15-17). Among the 614 respondents, 331 (54%) had vaginal lengthening treatment, 130 of whom (39%) had undergone surgical vaginal lengthening. Of individuals with Mayer-Rokitansky-Küster-Hauser syndrome, 428 of 614 (70%) reported having had one or more urinary symptoms, and 339 of 428 (79%) reported being bothered by these symptoms. Urinary symptoms included urinary incontinence (210 of 614 [34%]), urinary frequency (245 of 614 [40%]), urinary urgency (248 of 614 [40%]), pain with urination (97 of 614 [16%]), and recurrent urinary tract infections (177 of 614 [29%]). Prolapse symptoms included lower abdominal pressure (248 of 612 [41%]), pelvic heaviness or dullness (177 of 610 [29%]), and vaginal bulge (68 of 609 [11%]). In addition, constipation was reported by 153 of 611 respondents (25%), and anal incontinence was reported by 153 of 608 (25%) respondents. Beside recent urinary incontinence (P=.003) and anal incontinence (P<.001), the prevalence of pelvic floor symptoms (P>.05) did not differ significantly between those with and without vaginal lengthening. Among those with surgical vaginal lengthening, symptomatic vaginal bulge was highest in individuals who underwent a bowel vaginoplasty procedure. CONCLUSION: Urinary, prolapse, and bowel symptoms are common among individuals with Mayer-Rokitansky-Küster-Hauser syndrome and should be evaluated in this population. Overall, compared with no vaginal lengthening treatment, having vaginal lengthening treatment is not associated with substantial differences in the prevalence of pelvic floor symptoms, with the exception of recent urinary incontinence and anal incontinence. Our data suggested that bowel vaginoplasty may be associated with greater symptoms of vaginal bulge. More robust studies are needed to determine the impact of various vaginal lengthening treatments on pelvic floor symptoms.

Genetics of agenesis/hypoplasia of the uterus and vagina: narrowing down the number of candidate genes for Mayer-Rokitansky-Küster-Hauser Syndrome.

PURPOSE: Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome consists of congenital absence of the uterus and vagina and is often associated with renal, skeletal, cardiac, and auditory defects. The genetic basis is largely unknown except for rare variants in several genes. Many candidate genes have been suggested by mouse models and human studies. The purpose of this study was to narrow down the number of candidate genes. METHODS: Whole exome sequencing was performed on 111 unrelated individuals with MRKH; variant analysis focused on 72 genes suggested by mouse models, human studies of physiological candidates, or located near translocation breakpoints in t(3;16). Candidate variants (CV) predicted to be deleterious were confirmed by Sanger sequencing. RESULTS: Sanger sequencing verified 54 heterozygous CV from genes identified through mouse (13 CV in 6 genes), human (22 CV in seven genes), and translocation breakpoint (19 CV in 11 genes) studies. Twelve patients had ≥ 2 CVs, including four patients with two variants in the same gene. One likely digenic combination of LAMC1 and MMP14 was identified. CONCLUSION: We narrowed 72 candidate genes to 10 genes that appear more likely implicated. These candidate genes will require further investigation to elucidate their role in the development of MRKH.

From Engulfment to Enrichment: Associations Between Illness Representations, Self-Concept, and Psychological Adjustment in Mayer-Rokitansky-Küster-Hauser Syndrome.

STUDY OBJECTIVE: Mayer-Rokitansky-Küster-Hauser syndrome (MRKH) is a female reproductive disorder characterized by the absence or underdevelopment of the uterus, cervix and vagina. Limited research has examined factors related to psychological adjustment in MRKH. This study aimed to explore associations among illness representations, self-concept, psychological distress, and self-esteem in MRKH. DESIGN: Cross-sectional. SETTING: Participants were recruited globally online and from patient meetings. PARTICIPANTS: A total of 263 patients with MRKH (age 16.1-74.4 years; mean = 31.7 years) completed questionnaires. INTERVENTION: None. MAIN OUTCOME MEASURES: Validated self-reported measures of psychological distress and self-esteem (outcomes) and illness representations, self-concept, social support-seeking, and positive affect (hypothesized correlates) were explored in correlation and hierarchical regression analyses, alongside demographic and clinical variables. RESULTS: Younger age and shorter time since diagnosis was associated with higher distress and lower self-esteem. Patients with MRKH reported significantly higher distress and lower self-esteem than the general population. Higher distress and lower self-esteem were associated with higher reported engulfment (defining one's identity or feeling consumed by MRKH) and beliefs about the serious consequences of MRKH, and lower reported MRKH coherence, enrichment (positive changes to self-identity because of MRKH) and positive affect. CONCLUSIONS: Findings suggest that the impact of MRKH on identity plays an important role in adjustment. High perceived coherence and maintenance of positive affect may play a protective role in psychological adjustment. A 12-month follow-up study is planned to examine associations among these variables longitudinally. Baseline data suggest that early availability of psychological support would be beneficial, and interventions focused on identity and psychoeducation about MRKH would be valuable.

CIS-Acting Allele-Specific Expression Differences Induced by Alcohol and Impacted by Sex as Well as Parental Genotype of Origin.

BACKGROUND: Alcohol use disorders (AUDs) are influenced by complex interactions between the genetics of the individual and their environment. We have previously identified hundreds of polygenic genetic variants between the selectively bred high- and low-alcohol drinking (HAD and LAD) rat lines. Here, we report allele-specific expression (ASE) differences, between the HAD2 and LAD2 rat lines. METHODS: The HAD2 and LAD2 rats, which have been sequenced, were reciprocally crossed to generate 10 litters of F1 progeny. For 5 of these litters, the sire was HAD2, and for the other 5 litters, the sire was a LAD2. From these 10 litters, 2 males and 2 females were picked from each F1 litter (N = 40 total). The F1 pups were divided, balancing for sex and direction of cross, into an alcohol (15%) versus a water control group. Alcohol drinking started in the middle of adolescence (~postnatal day 35) and lasted 9 weeks. At the end of these treatments, rats were euthanized, the nucleus accumbens was dissected, and RNA was processed for RNA-sequencing and ASE analyses. RESULTS: Analyses revealed that adolescent ethanol (EtOH) drinking, individual EtOH drinking levels, parentage, and sex-of-animal affected ASEs of about 300 genes. The identified genes included those associated with EtOH metabolism (e.g., Aldh2); neuromodulatory function (e.g., Cckbr, Slc6a7, and Slc1a1); ion channel activity (e.g., Kcnc3); and other synaptic and epigenetic functions. CONCLUSIONS: These data indicate that EtOH drinking differentially amplified paternal versus maternal allelic contribution to the transcriptome. We hypothesize that this was due, at least in part, to EtOH-induced changes in cis-regulation of polymorphisms previously identified between the HAD2 and LAD2 rat lines. This report highlights the complexity of gene-by-environment interactions mediating a genetic predisposition for, and/or the active development of, AUDs.

Genetic analysis of Mayer-Rokitansky-Kuster-Hauser syndrome in a large cohort of families.

OBJECTIVE: To study the genetic cause of Mayer-Rokitansky-Kuster-Hauser syndrome (MRKH). Although a few candidate genes and genomic domains for have been reported for MRKH, the genetic underpinnings remain largely unknown. Some of the top candidate genes are WNT4, HNF1B, and LHX1. The goals of this study were to: 1) determine the prevalence of WNT4, HNF1B, and LHX1 point mutations, as well as new copy number variants (CNVs) in people with MRKH; and 2) identify and characterize MRKH cohorts. DESIGN: Laboratory- and community-based study. SETTING: Academic medical centers. PATIENT(S): A total of 147 MRKH probands and available family members. INTERVENTIONS(S): DNA sequencing of WNT4, HNF1B, and LHX1 in 100 MRKH patients, chromosomal microarray analysis in 31 North American MRKH patients, and characterization and sample collection of 147 North American and Turkish MRKH probands and their families. MAIN OUTCOME MEASURE(S): DNA sequence variants and CNVs; pedigree structural analysis. RESULT(S): We report finding CNVs in 6/31 people (∼19%) with MRKH, but no point mutations or small indels in WNT4, HNF1B, or LHX1 in 100 MRKH patients. Our MRKH families included 43 quads, 26 trios, and 30 duos. Of our MRKH probands, 87/147 (59%) had MRKH type 1 and 60/147 (41%) had type 2 with additional anomalies. CONCLUSION(S): Although the prevalence of WNT4, HNF1B, and LHX1 point mutations is low in people with MRKH, the prevalence of CNVs was ∼19%. Further analysis of our large familial cohort of patients will facilitate gene discovery to better understand the complex etiology of MRKH.

Preventing, treating, and predicting barbering: A fundamental role for biomarkers of oxidative stress in a mouse model of Trichotillomania.

Barbering, where a "barber" mouse plucks hair from its cagemates or itself, is both a spontaneously occurring abnormal behavior in mice and a well validated model of Trichotillomania (TTM). N-Acetylcysteine, (NAC) a cysteine derived food additive, is remarkably effective in treating TTM patients, but its mechanism of action is unknown. Reactive Oxygen Species (ROS), also known as free radicals, form as a natural byproduct of the normal metabolism of oxygen. Under normal circumstances, cells are able to defend themselves against ROS damage with antioxidant pathways. NAC is the precursor to the main antioxidant produced to defend the brain. Therefore, we hypothesized that barbering is a disease of oxidative stress, whereby ROS and/or a failure of antioxidant defenses leads to neuronal damage that induces barbering in susceptible animals. We tested this hypothesis in 32 female C57BL/6J mice by treating half with 1g/kg BW/day of NAC in their diet, and testing for protection against developing barbering behavior and curing of barbering behavior, and simultaneously testing for a panel of biomarkers of oxidative stress. NAC reduced the chance that mice would be barbers, and this effect did not differ between healthy (i.e. prevention) and affected animals (i.e. cure). Barbering animals had elevated urinary antioxidant capacity, indicative of oxidative stress, at all timepoints. Additionally, after treatment the risk of barbering increased with decreasing hydroxy-2'-deoxyguanosine (8-OHdG) levels, and with increasing glutathione (GSH) and oxidized glutathione (GSSG) levels, further indicating that barbering mice were under oxidative stress regardless of treatment with NAC. We did not find compelling evidence that urinary total antioxidant capacity, or urinary 8-OHdG, could predict response to NAC treatment. We conclude that NAC is effective in preventing and/or curing barbering at least in part by promoting GSH synthesis, thereby preventing oxidative damage.

High Resolution Genomic Scans Reveal Genetic Architecture Controlling Alcohol Preference in Bidirectionally Selected Rat Model.

Investigations on the influence of nature vs. nurture on Alcoholism (Alcohol Use Disorder) in human have yet to provide a clear view on potential genomic etiologies. To address this issue, we sequenced a replicated animal model system bidirectionally-selected for alcohol preference (AP). This model is uniquely suited to map genetic effects with high reproducibility, and resolution. The origin of the rat lines (an 8-way cross) resulted in small haplotype blocks (HB) with a corresponding high level of resolution. We sequenced DNAs from 40 samples (10 per line of each replicate) to determine allele frequencies and HB. We achieved ~46X coverage per line and replicate. Excessive differentiation in the genomic architecture between lines, across replicates, termed signatures of selection (SS), were classified according to gene and region. We identified SS in 930 genes associated with AP. The majority (50%) of the SS were confined to single gene regions, the greatest numbers of which were in promoters (284) and intronic regions (169) with the least in exon's (4), suggesting that differences in AP were primarily due to alterations in regulatory regions. We confirmed previously identified genes and found many new genes associated with AP. Of those newly identified genes, several demonstrated neuronal function involved in synaptic memory and reward behavior, e.g. ion channels (Kcnf1, Kcnn3, Scn5a), excitatory receptors (Grin2a, Gria3, Grip1), neurotransmitters (Pomc), and synapses (Snap29). This study not only reveals the polygenic architecture of AP, but also emphasizes the importance of regulatory elements, consistent with other complex traits.

A Study of Alterations in DNA Epigenetic Modifications (5mC and 5hmC) and Gene Expression Influenced by Simulated Microgravity in Human Lymphoblastoid Cells.

Cells alter their gene expression in response to exposure to various environmental changes. Epigenetic mechanisms such as DNA methylation are believed to regulate the alterations in gene expression patterns. In vitro and in vivo studies have documented changes in cellular proliferation, cytoskeletal remodeling, signal transduction, bone mineralization and immune deficiency under the influence of microgravity conditions experienced in space. However microgravity induced changes in the epigenome have not been well characterized. In this study we have used Next-generation Sequencing (NGS) to profile ground-based "simulated" microgravity induced changes on DNA methylation (5-methylcytosine or 5mC), hydroxymethylation (5-hydroxymethylcytosine or 5hmC), and simultaneous gene expression in cultured human lymphoblastoid cells. Our results indicate that simulated microgravity induced alterations in the methylome (~60% of the differentially methylated regions or DMRs are hypomethylated and ~92% of the differentially hydroxymethylated regions or DHMRs are hyperhydroxymethylated). Simulated microgravity also induced differential expression in 370 transcripts that were associated with crucial biological processes such as oxidative stress response, carbohydrate metabolism and regulation of transcription. While we were not able to obtain any global trend correlating the changes of methylation/ hydroxylation with gene expression, we have been able to profile the simulated microgravity induced changes of 5mC over some of the differentially expressed genes that includes five genes undergoing differential methylation over their promoters and twenty five genes undergoing differential methylation over their gene-bodies. To the best of our knowledge, this is the first NGS-based study to profile epigenomic patterns induced by short time exposure of simulated microgravity and we believe that our findings can be a valuable resource for future explorations.

The Lived Experience of MRKH: Sharing Health Information with Peers.

STUDY OBJECTIVE: To examine the process and emotional effect of disclosing a personal diagnosis of Mayer-Rokitansky-Küster-Hauser syndrome (MRKH) to peers during adolescence and young adulthood. DESIGN AND SETTING: Qualitative study using semistructured telephone interviews. PARTICIPANTS: Nine women diagnosed with MRKH, aged 21-31 years, recruited via patient support groups. INTERVENTIONS AND MAIN OUTCOME MEASURES: Motivators and barriers to self-disclosure of a diagnosis of MRKH to peers and partners. RESULTS: Motivators to tell peers about a diagnosis included significant trust in the relationship (whether platonic or romantic), needing to unload the experienced burden of diagnosis, and a sense of responsibility to be forthcoming if a long-term romantic future was desired. The most common barrier to telling others was fear of rejection or being labeled a "freak." Although most participants did not receive guidance from a health care provider regarding approaches to sharing diagnostic information with others, almost all participants reported wishing they had received such counseling. CONCLUSION: A diagnosis of MRKH elicits recurring anxieties about disclosure and the effect on relationships that are inadequately addressed by health care providers. Guidance and support on disclosure to friends and romantic partners should be provided whenever possible.

The hypomethylating agent Decitabine causes a paradoxical increase in 5-hydroxymethylcytosine in human leukemia cells.

The USFDA approved "epigenetic drug", Decitabine, exerts its effect by hypomethylating DNA, demonstrating the pivotal role aberrant genome-wide DNA methylation patterns play in cancer ontology. Using sensitive technologies in a cellular model of Acute Myeloid Leukemia, we demonstrate that while Decitabine reduces the global levels of 5-methylcytosine (5mC), it results in paradoxical increase of 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC) levels. Hitherto, the only biological mechanism known to generate 5hmC, 5fC and 5caC, involving oxidation of 5mC by members of Ten-Eleven-Translocation (TET) dioxygenase family, was not observed to undergo any alteration during DAC treatment. Using a multi-compartmental model of DNA methylation, we show that partial selectivity of TET enzymes for hemi-methylated CpG dinucleotides could lead to such alterations in 5hmC content. Furthermore, we investigated the binding of TET1-catalytic domain (CD)-GFP to DNA by Fluorescent Correlation Spectroscopy in live cells and detected the gradual increase of the DNA bound fraction of TET1-CD-GFP after treatment with Decitabine. Our study provides novel insights on the therapeutic activity of DAC in the backdrop of the newly discovered derivatives of 5mC and suggests that 5hmC has the potential to serve as a biomarker for monitoring the clinical success of patients receiving DAC.

Neuroepigenomics: Resources, Obstacles, and Opportunities.

Long-lived post-mitotic cells, such as the majority of human neurons, must respond effectively to ongoing changes in neuronal stimulation or microenvironmental cues through transcriptional and epigenomic regulation of gene expression. The role of epigenomic regulation in neuronal function is of fundamental interest to the neuroscience community, as these types of studies have transformed our understanding of gene regulation in post-mitotic cells. This perspective article highlights many of the resources available to researchers interested in neuroepigenomic investigations and discusses some of the current obstacles and opportunities in neuroepigenomics.

A snapshot of the hepatic transcriptome: ad libitum alcohol intake suppresses expression of cholesterol synthesis genes in alcohol-preferring (P) rats.

Research is uncovering the genetic and biochemical effects of consuming large quantities of alcohol. One prime example is the J- or U-shaped relationship between the levels of alcohol consumption and the risk of atherosclerotic cardiovascular disease. Moderate alcohol consumption in humans (about 30 g ethanol/d) is associated with reduced risk of coronary heart disease, while abstinence and heavier alcohol intake is linked to increased risk. However, the hepatic consequences of moderate alcohol drinking are largely unknown. Previous data from alcohol-preferring (P) rats showed that chronic consumption does not produce significant hepatic steatosis in this well-established model. Therefore, free-choice alcohol drinking in P rats may mimic low risk or nonhazardous drinking in humans, and chronic exposure in P animals can illuminate the molecular underpinnings of free-choice drinking in the liver. To address this gap, we captured the global, steady-state liver transcriptome following a 23 week free-choice, moderate alcohol consumption regimen (∼ 7.43 g ethanol/kg/day) in inbred alcohol-preferring (iP10a) rats. Chronic consumption led to down-regulation of nine genes in the cholesterol biosynthesis pathway, including HMG-CoA reductase, the rate-limiting step for cholesterol synthesis. These findings corroborate our phenotypic analyses, which indicate that this paradigm produced animals whose hepatic triglyceride levels, cholesterol levels and liver histology were indistinguishable from controls. These findings explain, at least in part, the J- or U-shaped relationship between cardiovascular risk and alcohol intake, and provide outstanding candidates for future studies aimed at understanding the mechanisms that underlie the salutary cardiovascular benefits of chronic low risk and nonhazardous alcohol intake.

Implications of genomic signatures in the differential vulnerability to fetal alcohol exposure in C57BL/6 and DBA/2 mice.

Maternal alcohol consumption inflicts a multitude of phenotypic consequences that range from undetectable changes to severe dysmorphology. Using tightly controlled murine studies that deliver precise amounts of alcohol at discrete developmental stages, our group and other labs demonstrated in prior studies that the C57BL/6 and DBA/2 inbred mouse strains display differential susceptibility to the teratogenic effects of alcohol. Since the phenotypic diversity extends beyond the amount, dosage and timing of alcohol exposure, it is likely that an individual's genetic background contributes to the phenotypic spectrum. To identify the genomic signatures associated with these observed differences in alcohol-induced dysmorphology, we conducted a microarray-based transcriptome study that also interrogated the genomic signatures between these two lines based on genetic background and alcohol exposure. This approach is called a gene x environment (GxE) analysis; one example of a GxE interaction would be a gene whose expression level increases in C57BL/6, but decreases in DBA/2 embryos, following alcohol exposure. We identified 35 candidate genes exhibiting GxE interactions. To identify cis-acting factors that mediated these interactions, we interrogated the proximal promoters of these 35 candidates and found 241 single nucleotide variants (SNVs) in 16 promoters. Further investigation indicated that 186 SNVs (15 promoters) are predicted to alter transcription factor binding. In addition, 62 SNVs created, removed or altered the placement of a CpG dinucleotide in 13 of the proximal promoters, 53 of which overlapped putative transcription factor binding sites. These 53 SNVs are also our top candidates for future studies aimed at examining the effects of alcohol on epigenetic gene regulation.

Cloning, annotation and developmental expression of the chicken intestinal MUC2 gene.

Intestinal mucin 2 (MUC2) encodes a heavily glycosylated, gel-forming mucin, which creates an important protective mucosal layer along the gastrointestinal tract in humans and other species. This first line of defense guards against attacks from microorganisms and is integral to the innate immune system. As a first step towards characterizing the innate immune response of MUC2 in different species, we report the cloning of a full-length, 11,359 bp chicken MUC2 cDNA, and describe the genomic organization and functional annotation of this complex, 74.5 kb locus. MUC2 contains 64 exons and demonstrates distinct spatiotemporal expression profiles throughout development in the gastrointestinal tract; expression increases with gestational age and from anterior to posterior along the gut. The chicken protein has a similar domain organization as the human orthologue, with a signal peptide and several von Willebrand domains in the N-terminus and the characteristic cystine knot at the C-terminus. The PTS domain of the chicken MUC2 protein spans ∼1600 amino acids and is interspersed with four CysD motifs. However, the PTS domain in the chicken diverges significantly from the human orthologue; although the chicken domain is shorter, the repetitive unit is 69 amino acids in length, which is three times longer than the human. The amino acid composition shows very little similarity to the human motif, which potentially contributes to differences in the innate immune response between species, as glycosylation across this rapidly evolving domain provides much of the musical barrier. Future studies of the function of MUC2 in the innate immune response system in chicken could provide an important model organism to increase our understanding of the biological significance of MUC2 in host defense and highlight the potential of the chicken for creating new immune-based therapies.

ENU mutagenesis reveals that Notchless homolog 1 (Drosophila) affects Cdkn1a and several members of the Wnt pathway during murine pre-implantation development.

BACKGROUND: Our interests lie in determining the genes and genetic pathways that are important for establishing and maintaining maternal-fetal interactions during pregnancy. Mutation analysis targeted to a 34 Mb domain flanked by Trp53 and Wnt3 demonstrates that this region of mouse chromosome 11 contains a large number of essential genes. Two mutant alleles (l11Jus1 and l11Jus4), which fall into the same complementation group, survive through implantation but fail prior to gastrulation. RESULTS: Through a positional cloning strategy, we discovered that these homozygous mutant alleles contain non-conservative missense mutations in the Notchless homolog 1 (Drosophila) (Nle1) gene. NLE1 is a member of the large WD40-repeat protein family, and is thought to signal via the canonical NOTCH pathway in vertebrates. However, the phenotype of the Nle1 mutant mice is much more severe than single Notch receptor mutations or even in animals in which NOTCH signaling is blocked. To test the hypothesis that NLE1 functions in multiple signaling pathways during pre-implantation development, we examined expression of multiple Notch downstream target genes, as well as select members of the Wnt pathway in wild-type and mutant embryos. We did not detect altered expression of any primary members of the Notch pathway or in Notch downstream target genes. However, our data reveal that Cdkn1a, a NOTCH target, was upregulated in Nle1 mutants, while several members of the Wnt pathway are downregulated. In addition, we found that Nle1 mutant embryos undergo caspase-mediated apoptosis as hatched blastocysts, but not as morulae or blastocysts. CONCLUSIONS: Taken together, these results uncover potential novel functions for NLE1 in the WNT and CDKN1A pathways during embryonic development in mammals.

Identification of 129S6/SvEvTac-specific polymorphisms on mouse chromosome 11.

Polymorphisms such as single-nucleotide polymorphisms (SNPs) and insertions/deletions (Indels) can be associated with phenotypic traits and be used as markers for disease diagnosis. Identification of these genetic variations within laboratory mice is crucial to improve our understanding of the genetic background of the mice used for research. As part of a positional cloning project, we sequenced six genes (Mettl16, Evi2a, Psmd11, Cct6d, Rffl, and Ap2b1) within a 6.8-Mb domain of mmu chr 11 in the C57BL/6J and 129S6/SvEvTac inbred strains. Although 129S6/SvEvTac is widely used in the mouse community, there is very little current (or projected future) sequence information available for this strain. We identified 6 Indels and 21 novel SNPs and confirmed genotype information for 114 additional SNPs in these 6 genes. Mettl16 and Ap2b1 contained the largest numbers of variants between the C57BL/6J and 129S6/SvEvTac strains. In addition, we found five new SNPs between 129S6/SvEvTac and 129S1/SvImJ within the Ap2b1 locus. Although we did not detect differences between C57BL/6J and 129S6/SvEvTac within Evi2a, this locus contains a relatively high SNP density compared with the surrounding sequence. Our study highlights the genetic differences among three inbred mouse strains (C57BL/6J, 129S6/SvEvTac, and 129S1/SvImJ) and provides valuable sequence information that can be used to track alleles in genomics-based studies.

Evolution of trefoil factor(s): genetic and spatio-temporal expression of trefoil factor 2 in the chicken (Gallus gallus domesticus).

Trefoil factors are essential healing initiators participating in mucosal reconstitution and tissue morphogenesis, especially on the surfaces of the gastrointestinal tract. This family has been cloned and characterized predominantly from mammals and amphibians. Avian species ingest stone and grit to help digest food, which may expose their gut to severe physical conditions. To further the understanding of the function of the TFF gene family across species, we undertook this research to clone, sequence, and characterize the spatio-temporal expression patterns of chicken TFF2 (ChTFF2) cDNA. Bioinformatics analysis of the promoter region and deduced amino acid sequence demonstrated that ChTFF2 contained unique characteristics; specifically the chicken promoter has multiple start sites and the protein contains a series of Lys-Lys-Val repeats. Unlike mammals, where TFF2 is detected primarily in the stomach, and occasionally in the proximal duodenum, chicken TFF2 transcripts are found throughout the gastrointestinal tract, with major expression sites in the glandular and muscular stomach as well as evident expression in the colon, small intestine, cecal tonsil and crop. Temporal analysis of intestinal ChTFF2 transcripts by quantitative RT-PCR showed high levels in embryos and a trend of constant expression during embryonic and post-hatch development, with a reduction occurring around hatch. Phylogenetic analysis highlighted the conservation of TFF proteins and functional divergence of trefoil domains, which suggest a transitional role in the bird during evolution.