Mechanisms of epigenetic regulation by C. elegans nuclear RNA interference pathways.

RNA interference (RNAi) is a highly conserved gene regulatory phenomenon whereby Argonaute/small RNA (AGO/sRNA) complexes target transcripts by antisense complementarity to modulate gene expression. While initially appreciated as a cytoplasmic process, RNAi can also occur in the nucleus where AGO/sRNA complexes are recruited to nascent transcripts. Nuclear AGO/sRNA complexes recruit co-factors that regulate transcription by inhibiting RNA Polymerase II, modifying histones, compacting chromatin and, in some organisms, methylating DNA. C. elegans has a longstanding history in unveiling the mechanisms of RNAi and has become an outstanding model to delineate the mechanisms underlying nuclear RNAi. In this review we highlight recent discoveries in the field of nuclear RNAi in C. elegans and the roles of nuclear RNAi in the regulation of gene expression, chromatin organization, genome stability, and transgenerational epigenetic inheritance.

A brief history of artificial intelligence embryo selection: from black-box to glass-box.

With the exponential growth of computing power and accumulation of embryo image data in recent years, artificial intelligence (AI) is starting to be utilized in embryo selection in IVF. Amongst different AI technologies, machine learning (ML) has the potential to reduce operator-related subjectivity in embryo selection while saving labor time on this task. However, as modern deep learning (DL) techniques, a subcategory of ML, are increasingly used, its integrated black-box attracts growing concern owing to the well-recognized issues regarding lack of interpretability. Currently, there is a lack of randomized controlled trials to confirm the effectiveness of such black-box models. Recently, emerging evidence has shown underperformance of black-box models compared to the more interpretable traditional ML models in embryo selection. Meanwhile, glass-box AI, such as interpretable ML, is being increasingly promoted across a wide range of fields and is supported by its ethical advantages and technical feasibility. In this review, we propose a novel classification system for traditional and AI-driven systems from an embryology standpoint, defining different morphology-based selection approaches with an emphasis on subjectivity, explainability, and interpretability.

Abnormal cleavage up to Day 3 does not compromise live birth and neonatal outcomes of embryos that have achieved full blastulation: a retrospective cohort study.

STUDY QUESTION: Do embryos displaying abnormal cleavage (ABNCL) up to Day 3 have compromised live birth rates and neonatal outcomes if full blastulation has been achieved prior to transfer? SUMMARY ANSWER: ABNCL is associated with reduced full blastulation rates but does not impact live birth rates and neonatal outcomes once full blastulation has been achieved. WHAT IS KNOWN ALREADY?: It is widely accepted that ABNCL is associated with reduced implantation rates of embryos when transferred at the cleavage stage. However, evidence is scarce in the literature reporting birth outcomes from blastocysts arising from ABNCL embryos, likely because they are ranked low priority for transfer. STUDY DESIGN, SIZE, DURATION: This retrospective cohort study included 1562 consecutive autologous in vitro fertilization cycles (maternal age 35.1 ± 4.7 years) performed at Fertility North, Australia between January 2017 and June 2022. Fresh transfers were performed on Day 3 or 5, with remaining embryos cultured up to Day 6 before vitrification. A total of 6019 embryos were subject to blastocyst culture, and a subset of 664 resulting frozen blastocysts was included for live birth and neonatal outcome analyses following single transfers. PARTICIPANTS/MATERIALS, SETTING, METHODS: ABNCL events were annotated from the first mitotic division up to Day 3, including direct cleavage (DC), reverse cleavage (RC) and <6 intercellular contact points at the 4-cell stage (<6ICCP). For DC and RC in combination, the ratios of affected blastomeres over the total number of all blastomeres up to Day 3 were also recorded. All pregnancies were followed up until birth with gestational age, birthweight, and sex of the baby being recorded. MAIN RESULTS AND THE ROLE OF CHANCE: Full blastulation rates for embryos showing DC (19.5%), RC (41.7%), <6ICCP (58.8%), and mixed (≥2) ABNCL types (26.4%) were lower than the rates for those without ABNCL (67.2%, P < 0.01 respectively). Subgroup analysis showed declining full blastulation rates with increasing ratios of combined DC/RC affected blastomeres over all blastomeres up to the 8-cell stage (66.2% when 0 affected, 47.0% when 0.25 affected, 27.4% when 0.5 affected, 14.5% when 0.75 affected, and 7.7% when all affected, P < 0.01). However, once full blastulation had been achieved, no difference was detected between DC, RC, <6ICCP, and no ABNCL blastocysts following single frozen transfers in subsequent live birth rates (25.9%, 33.0%, 36.0% versus 30.8%, P > 0.05, respectively), gestational age (38.7 ± 1.6, 38.5 ± 1.2, 38.3 ± 3.5 versus 38.5 ± 1.8 weeks, P > 0.05, respectively) and birthweight (3343.0 ± 649.1, 3378.2 ± 538.4, 3352.6 ± 841.3 versus 3313.9 ± 509.6 g, P > 0.05, respectively). Multiple regression (logistic or linear as appropriate) confirmed no differences in all of the above measures after accounting for potential confounders. LIMITATIONS, REASONS FOR CAUTION: Our study is limited by its retrospective nature, making it impossible to control every known or unknown confounder. Embryos in our dataset, being surplus after selection for fresh transfer, may not represent the general embryo population. WIDER IMPLICATIONS OF THE FINDINGS: Our findings highlight the incremental impact of ABNCL, depending on the ratio of affected blastomeres up to Day 3, on subsequent full blastulation. The reassuring live birth and neonatal outcomes of ABNCL blastocysts imply a potential self-correction mechanism among those embryos reaching the blastocyst stage, which provides valuable guidance for clinical practice and patient counseling. STUDY FUNDING/COMPETTING INTEREST(S): This research is supported by an Australian Government Research Training Program (RTP) Scholarship. All authors report no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

The Diversity Snowball Effect: The Quest to Increase Diversity in Emergency Medicine: A Case Study of Highland's Emergency Medicine Residency Program.

Blacks, Hispanics/Latinos, American Indians, Pacific Islanders, Alaska Natives, and Native Hawaiians make up 33% of the US population. These same groups are underrepresented in medicine. In 2013, the physician workforce was 4.1% black, 4.4% Hispanic/Latino, 0.4% American Indian or Alaska Native, 11.7% Asian, and 48.9% white. Only 9.9% of emergency physicians identify as underrepresented minority (4.5% black, 4.8% Hispanic/Latino, and 0.6% American Indian/Alaska Native). Efforts to increase the number of underrepresented minority physicians are important because previous studies show improved outcomes when the patient and physician share the same racial/ethnic background. Starting in 2006, the faculty at the Highland EM Residency Program in Oakland, CA, began a diversification initiative to increase the number of underrepresented minority residents. The goal was to closely mirror the US population and match 30% underrepresented minorities with each incoming class. After the initiative, there was a 2-fold increase in the number of underrepresented minority residents (from 12% to 27%). This article is a review of the strategies used to diversify the Highland EM Residency Program. Most components can be applied across emergency medicine programs to increase the number of underrepresented minority residents and potentially improve health outcomes for diverse populations.

The burden of prostate cancer in Trinidad and Tobago: one of the highest mortality rates in the world.

PURPOSE: In Trinidad and Tobago (TT), prostate cancer (CaP) is the most commonly diagnosed malignancy and the leading cause of cancer deaths among men. TT currently has one of the highest CaP mortality rates in the world. METHODS: 6,064 incident and 3,704 mortality cases of CaP occurring in TT from January 1995 to 31 December 2009 reported to the Dr. Elizabeth Quamina Cancer population-based cancer registry for TT, were analyzed to examine CaP survival, incidence, and mortality rates and trends by ancestry and geography. RESULTS: The age-standardized CaP incidence and mortality rates (per 100,000) based on the 1960 world-standardized in 2009 were 64.2 and 47.1 per 100,000. The mortality rate in TT increased between 1995 (37.9 per 100,000) and 2009 (79.4 per 100,000), while the rate in the US decreased from 37.3 per 100,000 to 22.1 per 100,000 over the same period. Fewer African ancestry patients received treatment relative to those of Indian and mixed ancestry (45.7%, 60.3%, and 60.9%, respectively). CONCLUSIONS: Notwithstanding the limitations surrounding data quality, our findings highlight the increasing burden of CaP in TT and the need for improved surveillance and standard of care. Our findings highlight the need for optimized models to project cancer rates in developing countries like TT. This study also provides the rationale for targeted screening and optimized treatment for CaP to ameliorate the rates we report.

Cancer incidence and mortality rates and trends in Trinidad and Tobago.

BACKGROUND: Cancer is the second leading cause of death in the Caribbean, including the islands of Trinidad and Tobago (TT). The population of TT consists of over 1.3 million people with diverse ancestral and sociocultural backgrounds, both of which may influence cancer incidence and mortality. The objective of this study was to examine incidence and mortality patterns and trends in TT. METHODS: Cancer surveillance data on 29,512 incident cancer cases reported to the Dr. Elizabeth Quamina Cancer Registry (population-based cancer registry of TT) between 1995 and 2009 were analyzed. Age-standardized rates, overall and by sex, ancestry, and geography, were reported. RESULTS: The highest incidence and mortality rates were observed for cancers related to reproductive organs in women, namely, breast, cervical, and uterine cancers, and prostate, lung and colorectal cancers among men. Average incidence rates were highest in areas covered by the Tobago Regional Health Authority (TRHA) (188 per 100,000), while average mortality rates were highest in areas covered by the North West Regional Health Authority (108 per 100,000). Nationals of African ancestry exhibited the highest rates of cancer incidence (243 per 100,000) and mortality (156 per 100,000) compared to their counterparts who were of East Indian (incidence, 125 per 100,000; mortality, 66 per 100,000) or mixed ancestry (incidence, 119 per 100,000; mortality, 66 per 100,000). CONCLUSIONS: Our findings highlight the need for national investment to improve the understanding of the epidemiology of cancer in Trinidad and Tobago, and to ultimately guide much needed cancer prevention and control initiatives in the near future.

Gynecologic cancer mortality in Trinidad and Tobago and comparisons of mortality-to-incidence rate ratios across global regions.

PURPOSE: To examine the factors associated with gynecologic cancer mortality risks, to estimate the mortality-to-incidence rate ratios (MIR) in Trinidad and Tobago (TT), and to compare the MIRs to those of select countries. METHODS: Data on 3,915 incident gynecologic cancers reported to the National Cancer Registry of TT from 1 January 1995 to 31 December 2009 were analyzed using proportional hazards models to determine factors associated with mortality. MIRs for cervical, endometrial, and ovarian cancers were calculated using cancer registry data (TT), GLOBOCAN 2012 incidence data, and WHO Mortality Database 2012 data (WHO regions and select countries). RESULTS: Among the 3,915 incident gynecologic cancers diagnosed in TT during the study period, 1,795 (45.8%) were cervical, 1,259 (32.2%) were endometrial, and 861 (22.0%) were ovarian cancers. Older age, African ancestry, geographic residence, tumor stage, and treatment non-receipt were associated with increased gynecologic cancer mortality in TT. Compared to GLOBOCAN 2012 data, TT MIR estimates for cervical (0.49 vs. 0.53), endometrial (0.61 vs. 0.65), and ovarian cancers (0.32 vs. 0.48) were elevated. While the Caribbean region had intermediate gynecologic cancer MIRs, MIRs in TT were among the highest of the countries examined in the Caribbean region. CONCLUSIONS: Given its status as a high-income economy, the relatively high gynecologic cancer MIRs observed in TT are striking. These findings highlight the urgent need for improved cancer surveillance, screening, and treatment for these (and other) cancers in this Caribbean nation.

A Comparison of Pain Beliefs and Coping Strategies and Their Association with Chronic Pain Adjustment Between Singapore and United States.

OBJECTIVES: Research examining the importance of pain beliefs and coping strategies to chronic pain adjustment has been performed almost exclusively using Western populations. The purpose of this study was to examine empirically the generalizability of this research to Singapore. METHODS: Employing a cross-sectional design, measures assessing pain beliefs, coping strategies, pain intensity, pain interference, and depressive symptoms were administered to 101 patients with chronic pain from Singapore. Analyses examined the means of belief and coping strategies measures and their associations with measures of pain intensity, pain interference, and depressive symptoms and compared the results with the data of a sample of 100 patients with chronic pain from a previously published study from the United States. RESULTS: Mean differences between the Singapore and US samples were found for four of the seven belief scales, and four of the eight coping scales. When significant, associations between belief and coping strategies with measures of pain and dysfunction were in the hypothesized directions in both samples. We also found that the strength of four out of 30 of the associations between beliefs/coping strategies and measures of pain and dysfunction were different between the Singapore and US samples. CONCLUSION: The findings provide further support for the potential influence of culture on how individuals view and cope with pain. However, the many similarities found in direction and strength of the associations between beliefs/coping strategies and measures of pain/dysfunction provide preliminary support for the appropriateness of the use of cognitive behavioral therapy developed in the United States with the Singapore population.

Impact of methods used to express levels of circulating fatty acids on the degree and direction of associations with blood lipids in humans.

Numerous studies have examined relationships between disease biomarkers (such as blood lipids) and levels of circulating or cellular fatty acids. In such association studies, fatty acids have typically been expressed as the percentage of a particular fatty acid relative to the total fatty acids in a sample. Using two human cohorts, this study examined relationships between blood lipids (TAG, and LDL, HDL or total cholesterol) and circulating fatty acids expressed either as a percentage of total or as concentration in serum. The direction of the correlation between stearic acid, linoleic acid, dihomo-γ-linolenic acid, arachidonic acid and DHA and circulating TAG reversed when fatty acids were expressed as concentrations v. a percentage of total. Similar reversals were observed for these fatty acids when examining their associations with the ratio of total cholesterol:HDL-cholesterol. This reversal pattern was replicated in serum samples from both human cohorts. The correlations between blood lipids and fatty acids expressed as a percentage of total could be mathematically modelled from the concentration data. These data reveal that the different methods of expressing fatty acids lead to dissimilar correlations between blood lipids and certain fatty acids. This study raises important questions about how such reversals in association patterns impact the interpretation of numerous association studies evaluating fatty acids and their relationships with disease biomarkers or risk.

Relationship between a common variant in the fatty acid desaturase (FADS) cluster and eicosanoid generation in humans.

Dramatic shifts in the Western diet have led to a marked increase in the dietary intake of the n-6 polyunsaturated fatty acid (PUFA), linoleic acid (LA). Dietary LA can then be converted to arachidonic acid (ARA) utilizing three enzymatic steps. Two of these steps are encoded for by the fatty acid desaturase (FADS) cluster (chromosome 11, 11q12.2-q13) and certain genetic variants within the cluster are highly associated with ARA levels. However, no study to date has examined whether these variants further influence pro-inflammatory, cyclooxygenase and lipoxygenase eicosanoid products. This study examined the impact of a highly influential FADS SNP, rs174537 on leukotriene, HETE, prostaglandin, and thromboxane biosynthesis in stimulated whole blood. Thirty subjects were genotyped at rs174537 (GG, n = 11; GT, n = 13; TT, n = 6), a panel of fatty acids from whole serum was analyzed, and precursor-to-product PUFA ratios were calculated as a marker of the capacity of tissues (particularly the liver) to synthesize long chain PUFAs. Eicosanoids produced by stimulated human blood were measured by LC-MS/MS. We observed an association between rs174537 and the ratio of ARA/LA, leukotriene B4, and 5-HETE but no effect on levels of cyclooxygenase products. Our results suggest that variation at rs174537 not only impacts the synthesis of ARA but the overall capacity of whole blood to synthesize 5-lipoxygenase products; these genotype-related changes in eicosanoid levels could have important implications in a variety of inflammatory diseases.

Environmental influence on cyanobacteria abundance and microcystin toxin production in a shallow temperate lake.

The increasing frequency of harmful cyanobacterial blooms in freshwater systems is a commonly recognized problem due to detrimental effects on water quality. Vancouver Lake, a shallow, tidally influenced lake in the flood plain of the Columbia River within the city of Vancouver, WA, USA, has experienced numerous summertime cyanobacterial blooms, dominated by Aphanizomenon sp. and Anabaena sp. Cyanobacteria abundance and toxin (microcystin) levels have been monitored in this popular urban lake for several years; however, no previous studies have identified which cyanobacteria species produce toxins, nor analyzed how changes in environmental variables contribute to the fluctuations in toxic cyanobacteria populations. We used a suite of molecular techniques to analyze water samples from Vancouver Lake over two summer bloom cycles (2009 and 2010). Both intracellular and extracellular microcystin concentrations were measured using an ELISA kit. Intracellular microcystin concentrations exceeded WHO guidelines for recreational waters several times throughout the sampling period. PCR results demonstrated that Microcystis sp. was the sole microcystin-producing cyanobacteria species present in Vancouver Lake, although Microcystis sp. was rarely detected in microscopical counts. qPCR results indicated that the majority of the Microcystis sp. population contained the toxin-producing gene (mcyE), although Microcystis sp. abundance rarely exceeded 1 percent of overall cyanobacteria abundance. Non-metric multidimensional scaling (NMDS) revealed that PO4-P was the main environmental variable influencing the abundance of toxic and non-toxic cyanobacteria, as well as intracellular microcystin concentrations. Our study underscores the importance of using molecular genetic techniques, in addition to traditional microscopy, to assess the importance of less conspicuous species in the dynamics of harmful algal blooms.

The influence of water quality variables on cyanobacterial blooms and phytoplankton community composition in a shallow temperate lake.

Cyanobacterial blooms and their detrimental effects on water quality have become a worldwide problem. Vancouver Lake, a tidally influenced shallow temperate freshwater lake in Washington state, U.S.A., exhibits annual summer cyanobacterial blooms that are of concern to local resource managers. Our objectives were to describe changes in phytoplankton community composition in Vancouver Lake over seasonal, annual, and interannual time scales, and to identify strong water quality predictors of phytoplankton community structure, with an emphasis on cyanobacterial blooms, from 2007 through 2010. Cluster analysis, indicator species analysis, and non-metric multidimensional scaling were used to identify significantly different phytoplankton community groupings and to determine which environmental factors influenced community changes. From 2007 through 2009, depletion of NO3-N followed by elevated PO4-P concentration was associated with increased biomass and duration of each cyanobacterial bloom. Time-lag analysis suggested that NO3-N availability contributed to interannual changes within the summer phytoplankton community. Specifically, in summer 2010, a distinct cyanobacteria community was not present, potentially due to increased NO3-N and decreased PO4-P and NH4-N availability. Our study provides a comprehensive assessment of species-level responses to water quality variables in a shallow non-stratifying temperate lake, contributes to a better understanding of phytoplankton dynamics, and may aid in predicting and managing cyanobacterial blooms.

The impact of polyunsaturated fatty acid-based dietary supplements on disease biomarkers in a metabolic syndrome/diabetes population.

BACKGROUND: Ingestion of polyunsaturated fatty acids (PUFAs) has been proposed to influence several chronic diseases including coronary heart disease (CHD) and type-2 diabetes (T2D).There is strong evidence that omega-3 (n-3) PUFAs provide protection against CHD and biomarkers of atherosclerosis. In contrast, there is more limited and inconsistent data for T2D. Few studies have examined the impact of n-3 PUFA-containing botanical oils on T2D. METHODS: Fifty-nine subjects with early-stageT2D or metabolic syndrome participated in an 8-week, randomized, single-blind, parallel intervention study and were provided PUFA-containing oils. Individuals received either corn oil (CO), a botanical oil (BO) combination (borage [Borago officinalis L.]/echium oil [Echium plantagineum L.]) or fish oil (FO). The BO combination was enriched in alpha-linolenic, gamma-linolenic, and stearidonic acids and the FO in eicosapentaenoic and docosahexaenoic acids. Serum fatty acids and other serum lipids(triglycerides and total, HDL and LDL cholesterol), as well as markers of inflammation (leptin, and C-reactive protein) and glucose regulation (glucose and hemoglobin A1c) were assessed from fasting participants at baseline and after the intervention. RESULTS: Compliance was verified by expected increases in specific PUFAs in each of the three oil arms. Participants in the CO group showed no differences in serum lipids, markers of inflammation or glucose regulation between pre- and post-treatment measures. Supplementation with BO significantly lowered total and LDL cholesterol levels and FO reduced serum triglycerides, hemoglobin A1c and increased HDL-cholesterol. CONCLUSION: Short-term dietary supplementation with BO and FO improved biomarkers associated with T2D/metabolic syndrome. TRIAL REGISTRATION: Clinicaltrial.gov NCT01145066.

Associations between Preschool Teachers' Food-Based Learning Frequency, Level of Personal Priority and Identified Resources and Challenges: A Needs Assessment.

Food-based learning (FBL) is the use of food as a teaching tool in the classroom, which can expose children to healthy foods to improve preference and consumption. However, more research is needed on the use and perception of FBL in the Head Start (HS) preschool classroom. In an online survey, we explored associations between North Carolina HS teachers' (n = 168) experiences (e.g., resources, challenges, needs, and preferences) with FBL, how frequently teachers implemented it, and how much they prioritized it. We used frequencies and chi-square tests of independence to assess associations between study variables. Teachers reported using FBL regularly with access to FBL resources (e.g., books and center play materials) and experiencing challenges (e.g., lack of funding and material resources). Teachers partnered with parents and farmers markets and expressed a need for additional FBL professional development. Our needs assessment findings revealed specific resources, challenges, and perceptions significantly associated with how often teachers used FBL and their priority level. Additional research should investigate how to alleviate FBL challenges and strategies to create policy and environmental changes that facilitate early FBL.

Resveratrol and its metabolites elicit neuroprotection via high-affinity binding to the laminin receptor at low nanomolar concentrations.

Resveratrol prevents various neurodegenerative diseases in animal models despite reaching only low nanomolar concentrations in the brain after oral administration. In this study, based on the quenching of intrinsic tryptophan fluorescence and molecular docking, we found that trans-resveratrol, its conjugates (glucuronide and sulfate), and dihydro-resveratrol (intestinal microbial metabolite) bind with high affinities (Kd, 0.2-2 nm) to the peptide G palindromic sequence (near glycosaminoglycan-binding motif) of the 67-kDa laminin receptor (67LR). Preconditioning with low concentrations (0.01-10 nm) of these polyphenols, especially resveratrol-glucuronide, protected neuronal cells from death induced by serum withdrawal via activation of cAMP-mediated signaling pathways. This protection was prevented by a 67LR-blocking antibody, suggesting a role for this cell-surface receptor in neuroprotection by resveratrol metabolites.

Integration of Food-based Learning With Science in the Preschool Classroom: Implementation Gaps and Opportunities.

OBJECTIVE: To explore Head Start teachers' use and integration of food-based learning (FBL) with science learning in the Head Start classroom. DESIGN: Phenomenological approach using in-depth semistructured telephone interviews. SETTING: North Carolina Head Start preschools. PARTICIPANTS: Thirty-five Head Start lead and assistant teachers. PHENOMENON OF INTEREST: All interviews were transcribed verbatim. Authors coded interview data for emergent themes. ANALYSIS: Eleven primary themes were identified during analysis and inductively organized using the Systems Thinking Iceberg Model. RESULTS: Teachers described most frequently using FBL during mealtimes. Teachers stated they felt successful when children were engaged and willing to try a new food. However, they struggled to connect food to science concepts. Teachers reported several motivators (eg, improving health) and barriers (eg, food waste) to integrating FBL. Teachers prioritized preparing children for kindergarten, but most teachers did not see how FBL could help them achieve this goal. CONCLUSIONS AND IMPLICATIONS: Head Start teacher professional development programs could impact all 4 levels of the Systems Thinking Model to improve teachers' perceptions, underlying structures, and mental models regarding integrative FBL. Additional research is warranted to investigate the adoption, implementation, and potential impact of FBL on academic outcomes.

Co-occupancy of two Pumilio molecules on a single hunchback NRE.

Pumilio controls a number of processes in eukaryotes, including the translational repression of hunchback (hb) mRNA in early Drosophila embryos. The Pumilio Puf domain binds to a pair of 32 nucleotide (nt) Nanos response elements (NRE1 and NRE2) within the 3' untranslated region of hb mRNA. Despite the elucidation of structures of human Pumilio Puf domain in complex with hb RNA elements, the nature of hb mRNA recognition remains unclear. In particular, the site that mediates regulation in vivo is significantly larger than the 8-10-nt RNA elements bound to single Puf molecules in crystal structures. Here we present biophysical and biochemical data that partially resolve the paradox. We show that each NRE is composed of two binding sites (Box A and Box B) and that two Puf domains can co-occupy a single NRE. The Puf domains have a higher affinity for the 3' Box B site than the 5' Box A site; binding to the intact NRE appears to be cooperative (at least in some experiments). We suggest that the 2 Pumilio:1 NRE complex is the functional regulatory unit in vivo.

Emerging Roles for Chromo Domain Proteins in Genome Organization and Cell Fate in C. elegans.

In most eukaryotes, the genome is packaged with histones and other proteins to form chromatin. One of the major mechanisms for chromatin regulation is through post-translational modification of histone proteins. Recognition of these modifications by effector proteins, often dubbed histone "readers," provides a link between the chromatin landscape and gene regulation. The diversity of histone reader proteins for each modification provides an added layer of regulatory complexity. In this review, we will focus on the roles of chromatin organization modifier (chromo) domain containing proteins in the model nematode, Caenorhabditis elegans. An amenability to genetic and cell biological approaches, well-studied development and a short life cycle make C. elegans a powerful system to investigate the diversity of chromo domain protein functions in metazoans. We will highlight recent insights into the roles of chromo domain proteins in the regulation of heterochromatin and the spatial conformation of the genome as well as their functions in cell fate, fertility, small RNA pathways and transgenerational epigenetic inheritance. The spectrum of different chromatin readers may represent a layer of regulation that integrates chromatin landscape, genome organization and gene expression.

The molecular chaperone Hsp90 is required for mRNA localization in Drosophila melanogaster embryos.

Localization of maternal nanos mRNA to the posterior pole is essential for development of both the abdominal segments and primordial germ cells in the Drosophila embryo. Unlike maternal mRNAs such as bicoid and oskar that are localized by directed transport along microtubules, nanos is thought to be trapped as it swirls past the posterior pole during cytoplasmic streaming. Anchoring of nanos depends on integrity of the actin cytoskeleton and the pole plasm; other factors involved specifically in its localization have not been described to date. Here we use genetic approaches to show that the Hsp90 chaperone (encoded by Hsp83 in Drosophila) is a localization factor for two mRNAs, nanos and pgc. Other components of the pole plasm are localized normally when Hsp90 function is partially compromised, suggesting a specific role for the chaperone in localization of nanos and pgc mRNAs. Although the mechanism by which Hsp90 acts is unclear, we find that levels of the LKB1 kinase are reduced in Hsp83 mutant egg chambers and that localization of pgc (but not nos) is rescued upon overexpression of LKB1 in such mutants. These observations suggest that LKB1 is a primary Hsp90 target for pgc localization and that other Hsp90 partners mediate localization of nos.

Monitoring Pc 4 photodynamic therapy in clinical trials of cutaneous T-cell lymphoma using noninvasive spectroscopy.

Silicon phthalocyanine Pc 4 photodynamic therapy (Pc 4-PDT) has emerged as a potentially effective treatment for cutaneous T-cell lymphoma (CTCL). Noninvasive reflectance and fluorescence spectroscopy before, during, and after PDT may provide useful dose metrics and enable therapy to be tailored to individual lesions. We present the design and implementation of a portable bedside spectroscopy system for initial clinical trials of Pc 4-PDT of CTCL. Reflectance and fluorescence spectra were obtained from an early stage CTCL patient throughout the course of the PDT treatment. Preliminary patient data show a significant effect of Pc 4 on the tissue absorption, modest Pc 4 photobleaching, and heterogeneity of Pc 4 within and between the lesions.