The SIN3 corepressor serves as a scaffold for the assembly of histone deacetylase (HDAC) complexes. SIN3 and its associated HDAC have been shown to have critical roles in both development and the regulation of cell cycle progression. Although multiple SIN3 isoforms have been reported in simple to complex eukaryotic organisms, the mechanisms by which such isoforms regulate specific biological processes are still largely uncharacterized. To gain insight into how SIN3 isoform-specific function contributes to the growth and development of a metazoan organism, we have affinity-purified two SIN3 isoform-specific complexes, SIN3 187 and 220, from Drosophila S2 cells and embryos. We have identified a number of proteins common to the complexes, including the HDAC RPD3, as well as orthologs of several proteins known to have roles in regulating cell proliferation in other organisms. We additionally identified factors, including the histone demethylase little imaginal discs and histoneinteracting protein p55, that exhibited a preferential interaction with the largest SIN3 isoform. Our experiments indicate that the isoforms are associated with distinct HDAC activity and are recruited to unique and shared sites along polytene chromosome arms. Furthermore, although expression of SIN3 220 can substitute for genetic loss of other isoforms, expression of SIN3 187 does not support Drosophila viability. Together our findings suggest that SIN3 isoforms serve distinct roles in transcriptional regulation by partnering with different histone-modifying enzymes. Transcriptional regulation by SIN3 histone deacetylase (HDAC)2 complexes is essential for a number of important biological processes. For instance, SIN3 complexes are required for viability, as demonstrated by the finding that mutations in SIN3 result in embryonic lethality in both Drosophila and mouse (1-4). Furthermore, genome-wide localization and gene expression studies have mapped the SIN3 regulatory network to include nuclear genes involved in mitochondrial biogenesis and function (5), genes involved in DNA replication and repair (6), and genes involved in development (2, 5, 6). Additionally, functional studies in both Drosophila and mammalian systems have shown that SIN3 is an important factor in the regulation of cell cycle progression and exit (2, 3, 7-10). Together, these studies highlight the importance of SIN3 in both growth and development.The SIN3 corepressor serves as a scaffold for the assembly of HDAC complexes. These complexes are recruited to chromatin, where the catalytic subunit, RPD3 in yeast and Drosophila and HDAC1 and -2 in mammals, deacetylates histones to repress transcription (11,12). Compositionally similar SIN3 complexes from Saccharomyces cerevisiae, Schizosaccharomyces pombe, and mammals have been isolated and characterized, illustrating the conservation of SIN3 complex proteins among eukaryotes (11, 13). This similarity further suggests that the essential functions of these complexes may be conserved as well.In yeast, two distinct mechanisms of SI...

SIN3 is a component of a histone deacetylase complex known to be important for transcription repression. While multiple isoforms of SIN3 have been reported, little is known about their relative expression or role in development. Using a combination of techniques, we have determined that SIN3 is expressed throughout the Drosophila life cycle. The pattern of expression for each individual isoform, however, is distinct. Knock down of all SIN3 expression reveals a requirement for this protein in embryonic and larval periods. Taken together, the data suggest that SIN3 is required for multiple developmental events during the Drosophila life cycle. Developmental Dynamics 237:3040 -3050, 2008.

Dollar spot, caused by Sclerotinia homoeocarpa, is a prevalent turfgrass disease, and the fungus exhibits widespread fungicide resistance in North America. In a previous study, an ABC-G transporter, ShatrD, was associated with practical field resistance to demethylation inhibitor (DMI) fungicides. Mining of ABC-G transporters, also known as pleiotropic drug resistance (PDR) transporters, from RNA-Seq data gave an assortment of transcripts, several with high sequence similarity to functionally characterized transporters from Botrytis cinerea, and others with closest blastx hits from Aspergillus and Monilinia. In addition to ShatrD, another PDR transporter showed significant over-expression in replicated RNA-Seq data, and in a collection of field-resistant isolates, as measured by quantitative polymerase chain reaction. These isolates also showed reduced sensitivity to unrelated fungicide classes. Using a yeast complementation system, we sought to test the hypothesis that this PDR transporter effluxes DMI as well as chemically unrelated fungicides. The transporter (ShPDR1) was cloned into the Gal1 expression vector and transformed into a yeast PDR transporter deletion mutant, AD12345678. Complementation assays indicated that ShPDR1 complemented the mutant in the presence of propiconazole (DMI), iprodione (dicarboximide) and boscalid (SDHI, succinate dehydrogenase inhibitor). Our results indicate that the over-expression of ShPDR1 is correlated with practical field resistance to DMI fungicides and reduced sensitivity to dicarboximide and SDHI fungicides. These findings highlight the potential for the eventual development of a multidrug resistance phenotype in this pathogen. In addition, this study presents a pipeline for the discovery and validation of fungicide resistance genes using de novo next-generation sequencing and molecular biology techniques in an unsequenced plant pathogenic fungus.

The transcriptional corepressor SIN3 is an essential gene in metazoans. In cell culture experiments, loss of SIN3 leads to defects in cell proliferation. Whether and how SIN3 may regulate the cell cycle during development has not been explored. To gain insight into this relationship, we have generated conditional knock down of Drosophila SIN3 and analyzed effects on growth and development in the wing imaginal disc. We find that loss of SIN3 affects normal cell growth and leads to down regulation of expression of the cell cycle regulator gene String (STG). A SIN3 knock down phenotype can be suppressed by overexpression either of STG or of Cdk1, the target of STG phosphatase. These data link SIN3 and STG in a genetic pathway that affects cell cycle progression in a developing tissue.

The importance of neurorehabilitation services for people with disabilities is getting well-recognized in low- and middle-income countries (LMICs) recently. However, accessibility to the same has remained the most significant challenge, in these contexts. This is especially because of the non-availability of trained specialists and the availability of neurorehabilitation centers only in urban cities owned predominantly by private healthcare organizations. In the current COVID-19 pandemic, the members of the Task Force for research at the Indian Federation of Neurorehabilitation (IFNR) reviewed the context for tele-neurorehabilitation (TNR) and have provided the contemporary implications for practicing TNR during COVID-19 for people with neurological disabilities (PWNDs) in LMICs. Neurorehabilitation is a science that is driven by rigorous research-based evidence. The current pandemic implies the need for systematically developed TNR interventions that is evaluated for its feasibility and acceptability and that is informed by available evidence from LMICs. Given the lack of organized systems in place for the provision of neurorehabilitation services in general, there needs to be sufficient budgetary allocations and a sector-wide approach to developing policies and systems for the provision of TNR services for PWNDs. The pandemic situation provides an opportunity to optimize the technological innovations in health and scale up these innovations to meet the growing burden of neurological disability in LMICs. Thus, this immense opportunity must be tapped to build capacity for safe and effective TNR services provision for PWNDs in these settings.

Post-translational modification of histones is a major mechanism of epigenetic regulation of eukaryotic transcription. Drosophila has proven to be an important model system for the study of histone modifying enzymes and the cross talk that occurs between the various modifications. Polytene chromosome analysis and genome-wide chromatin immunoprecipitation (ChIP) studies have provided much insight into the location of marks and many of the enzymes that perform the catalytic reactions. Gene specific effects have been determined through study of flies carrying mutations in histone modifying enzymes. This review will highlight classic studies and present recent progress on both the localization data and mutant analyses. This information has been used to assign function to the marks and to the enzymes that place or remove them, critical for the process of transcriptional regulation.

The role of the Sin3A transcriptional corepressor in regulating the cell cycle is established in various metazoans. Little is known, however, about the signaling pathways that trigger or are triggered by Sin3A function. To discover genes that work in similar or opposing pathways to Sin3A during development, we have performed an unbiased screen of deficiencies of the Drosophila third chromosome. Additionally, we have performed a targeted loss of function screen to identify cell cycle genes that genetically interact with Sin3A. We have identified genes that encode proteins involved in regulation of gene expression, signaling pathways and cell cycle that can suppress the curved wing phenotype caused by the knockdown of Sin3A. These data indicate that Sin3A function is quite diverse and impacts a wide variety of cellular processes.

SummaryThe Saccharomyces cerevisiae PHO5 gene product accounts for a majority of the acid phosphatase activity. Its expression is induced by the basic helix-loophelix (bHLH) protein, Pho4p, in response to phosphate depletion. Pho4p binds predominantly to two UAS elements (UASp1 at -356 and UASp2 at -247) in the PHO5 promoter. Previous studies from our lab have shown cross-regulation of different biological processes by bHLH proteins. This study tested the ability of all yeast bHLH proteins to regulate PHO5 expression and identified inositol-mediated regulation via the Ino2p/Ino4p bHLH proteins. Ino2p/Ino4p are known regulators of phospholipid biosynthetic genes. Genetic epistasis experiments showed that regulation by inositol required a third UAS site (UASp3 at -194). ChIP assays showed that Ino2p:Ino4p bind the PHO5 promoter and that this binding is dependent on Pho4p binding. These results demonstrate that phospholipid biosynthesis is co-ordinated with phosphate utilization via the bHLH proteins.