Segregation between an ornamental and a disease driver gene provides insights into pigment cell regulation.

Genetic interactions are adaptive within a species. Hybridization can disrupt such species-specific genetic interactions and creates novel interactions that alter the hybrid progeny overall fitness. Hybrid incompatibility, which refers to degenerative genetic interactions that decrease the overall hybrid survival, is one of the results from combining two diverged genomes in hybrids. The discovery of spontaneous lethal tumorigenesis and underlying genetic interactions in select hybrids between diverged Xiphophorus species showed that lethal pathological process can result from degenerative genetic interactions. Such genetic interactions leading to lethal phenotype are thought to shield gene flow between diverged species. However, hybrids between certain Xiphophorus species do not develop such tumors. Here we report the identification of a locus residing in the genome of one Xiphophorus species that represses an oncogene from a different species. Our finding provides insights into normal and pathological pigment cell development, regulation and molecular mechanism in hybrid incompatibility. Significance: The Dobzhansky-Muller model states epistatic interactions occurred between genes in diverged species underlies hybrid incompatibility. There are a few vertebrate interspecies hybrid cases that support the Dobzhansky-Muller model. This study reports a fish hybrid system where incompatible genetic interactions are involved in neuronal regulation of pigment cell biology, and also identified a novel point of regulation for pigment cells.

Campylobacter infection promotes IFNγ-dependent intestinal pathology via ILC3 to ILC1 conversion.

Innate lymphoid cells (ILCs) are a heterogeneous family of immune regulators that protect against mucosal pathogens but can also promote intestinal pathology. Although the plasticity between ILCs populations has been described, the role of mucosal pathogens in inducing ILC conversion leading to intestinal pathology remains unclear. Here we demonstrate that IFNγ-producing ILCs are responsible for promoting intestinal pathology in a mouse model of enterocolitis caused by Campylobacter jejuni, a common human enteric pathogen. Phenotypic analysis revealed a distinct population of IFNγ-producing NK1.1-T-bet+ILCs that accumulated in the intestine of C. jejuni-infected mice. Adoptive transfer experiments demonstrated their capacity to promote intestinal pathology. Inactivation of T-bet in NKp46+ ILCs ameliorated disease. Transcriptome analysis and cell-fate mapping experiments revealed that IFNγ-producing NK1.1-ILCs correspond to ILC1 profile and develop from RORγt+ progenitors. Collectively, we identified a distinct population of NK1.1-ex-ILC3s that promotes intestinal pathology through IFNγ production in response to C. jejuni infection.

Reliable approaches to extract high-integrity RNA from skin and other pertinent tissues used in pain research.

INTRODUCTION: Comprehensive mRNA sequencing is a powerful tool for conducting unbiased, quantitative differential gene expression analysis. However, the reliability of these data is contingent on the extraction of high-quality RNA from samples. Preserving RNA integrity during extraction can be problematic, especially in tissues such as skin with dense, connective matrices and elevated ribonuclease expression. This is a major barrier to understanding the influences of altered gene expression in many preclinical pain models and clinical pain disorders where skin is the site of tissue injury. OBJECTIVE: This study developed and evaluated extraction protocols for skin and other tissues to maximize recovery of high-integrity RNA needed for quantitative mRNA sequencing. METHODS: Rodent and human tissue samples underwent one of the several different protocols that combined either RNA-stabilizing solution or snap-freezing with bead milling or cryosectioning. Indices of RNA integrity and purity were assessed for all samples. RESULTS: Extraction of high-integrity RNA is highly dependent on the methods used. Bead-milling skin collected in RNA-stabilizing solution resulted in extensive RNA degradation. Snap-freezing in liquid nitrogen was required for skin and highly preferable for other tissues. Skin also required cryosectioning to achieve effective penetration of RNA-stabilizing solution to preserve RNA integrity, whereas bead milling could be used instead with other tissues. Each method was reproducible across multiple experimenters. Electrophoretic anomalies that skewed RNA integrity value assignment required manual correction and often resulted in score reduction. CONCLUSION: To achieve the potential of quantitative differential gene expression analysis requires verification of tissue-dependent extraction methods that yield high-integrity RNA.

Association of chromosome 8q variants with prostate cancer risk in Caucasian and Hispanic men.

Genotyping of a 615 kb region within 8q24 with 49 haplotype-tagged single-nucleotide polymorphisms (SNPs) in 2109 samples (797 cases and 1312 controls) of two ethnic/racial groups found SNPs that are significantly associated with the risk for prostate cancer (PCa). The highest significance in Caucasian men was found for rs6983267; the AA genotype reduced the risk for PCa [odds ratio (OR) = 0.48, 95% confidence interval (CI) = 0.35-0.65, P = 2.74 x 10(-6)]. This SNP also had a significant independent effect from other SNPs in the region in this group. In Hispanic men, rs7837328 and rs921146 showed independent effects (OR = 2.55, 95% CI = 1.51-4.31, P = 4.33 x 10(-4), OR = 2.09, 95% CI = 1.40-3.12, P = 3.13 x 10(-4), respectively). Significant synergist effects for increasing numbers of high-risk alleles were found in both ethnicities. Haplotype analysis revealed major haplotypes, containing the non-risk alleles, conferred protection against PCa. We found high linkage disequilibrium between significant SNPs within the region and SNPs within the CUB and Sushi Multiple Domains 1 gene (CSMD1), on the short arm of chromosome 8 in both ethnicities. These data suggest that multiple interacting SNPs within 8q24, as well as different regions on chromosome 8 far beyond this 8q24 candidate region, may confer increased risk of PCa. This is the first report to investigate the involvement of 8q24 variants in the susceptibility for PCa in Hispanic men.

Three novel mutations in SQSTM1 identified in familial Paget's disease of bone.

UNLABELLED: Mutations in Sequestosome 1 (SQSTM1) have been shown to segregate with familial Paget's disease of bone (PDB). We examined the coding sequence of SQSTM1 in five PDB pedigrees and found three novel mutations clustered around the C-terminal ubiquitin associated domain. Disruptions of the C-terminal domain of SQSTM1 seem to be a leading cause of familial PDB. INTRODUCTION: The characteristic features of Paget's disease of bone (PDB) are caused by focal areas of excessive and uncoordinated bone remodeling. A total of seven genetic loci (PDB1-PDB7) have been reported to be associated with the disease. The gene for Sequestosome 1 (p62; SQSTM1) has been identified as the causative gene for PDB3 in numerous French-Canadian families and families predominantly of British descent. To date, a total of three mutations, all affecting the ubiquitin-associated domain of SQSTM1, have been identified: a single 1215 C to T (P392L) transversion in exon 8, a T insertion in exon 8 (E396X), and a G to A mutation at the splice junction of exon 7 (IVS7 + 1). MATERIALS AND METHODS: DNA was isolated from blood collected from the members of five U.S. PDB pedigrees. Mutation analysis of the coding sequence of the SQSTM1 gene was performed on the proband and other key individuals in the pedigrees. RESULTS: Four of the five families had SQSTM1 mutations. Three of these mutations were novel: a single base deletion in exon 8 at position 1210 (1210delT) resulting in a premature stop codon at amino acid 394, a single C deletion in exon 8 at position 1215 (1215delC) also resulting in a premature stop codon at amino acid 394, and a single 1200 C to T (P387L) transversion in exon 7. CONCLUSION: Noteworthy is the fact that these three SQSTM1 mutations, in addition to the three previously described mutations, are clustered near the C-terminal of the protein. These mutations may be acting in a dominant-negative fashion to disrupt the ubiquitin-binding function, which could result in abnormal activation of the NF-kappaB pathway and the subsequent activation of the osteoclasts. These findings imply that SQSTM1 mutations may play a role in the majority of familial PDB in the United States.

Single and multigenic analysis of the association between variants in 12 steroid hormone metabolism genes and risk of prostate cancer.

To estimate the prostate cancer risk conferred by individual single nucleotide polymorphisms (SNPs), SNP-SNP interactions, and/or cumulative SNP effects, we evaluated the association between prostate cancer risk and the genetic variants of 12 key genes within the steroid hormone pathway (CYP17, HSD17B3, ESR1, SRD5A2, HSD3B1, HSD3B2, CYP19, CYP1A1, CYP1B1, CYP3A4, CYP27B1, and CYP24A1). A total of 116 tagged SNPs covering the group of genes were analyzed in 2,452 samples (886 cases and 1,566 controls) in three ethnic/racial groups. Several SNPs within CYP19 were significantly associated with prostate cancer in all three ethnicities (P = 0.001-0.009). Genetic variants within HSD3B2 and CYP24A1 conferred increased risk of prostate cancer in non-Hispanic or Hispanic Caucasians. A significant gene-dosage effect for increasing numbers of potential high-risk genotypes was found in non-Hispanic and Hispanic Caucasians. Higher-order interactions showed a seven-SNP interaction involving HSD17B3, CYP19, and CYP24A1 in Hispanic Caucasians (P = 0.001). In African Americans, a 10-locus model, with SNPs located within SRD5A2, HSD17B3, CYP17, CYP27B1, CYP19, and CYP24A1, showed a significant interaction (P = 0.014). In non-Hispanic Caucasians, an interaction of four SNPs in HSD3B2, HSD17B3, and CYP19 was found (P < 0.001). These data are consistent with a polygenic model of prostate cancer, indicating that multiple interacting genes of the steroid hormone pathway confer increased risk of prostate cancer.