Analysing The Effects Of Loss Of Sin3 In Drosophila Melanogaster

Sin3A has been previously shown to be an essential gene for Drosophila viability and is implicated in the regulation of cell cycle. In this study, we show that SIN3 is not only required for embryonic viability but also for post-embryonic development. Genetic analysis suggests that the different isoforms of SIN3 may regulate unique sets of genes during development. The developmental lethality occurring due to ubiquitous knock down of SIN3 is hypothesized to be to the result of defects in cell proliferation. Conditional knock down of SIN3 in the wing discs results in a curly wing phenotype in the adult fly. These wings are smaller and have fewer cells resulting from a defect in cell proliferation. This is visualized in the form of smaller SIN3 knockdown clones in the wing discs. Furthermore, loss of SIN3 results in a decrease in the number of mitotic cells in the wing discs. This is in part due to misregulation of the G2/M phase of the cell cycle. SIN3 genetically interacts with STG, a protein important for the G2/M phase of the cell cycle. Loss of SIN3 results in downregulation of STG whereas overexpression of STG in a SIN3 knockdown background is able to rescue the curly wing phenotype. SIN3 also genetically interacts with other genes involved in the cell cycle like Cdk2 and Cdc16 suggesting that SIN3 plays a role in multiple phases of the cell cycle. SIN3 also genetically interacts with genes involved in the Wnt and Toll signaling pathways, the mediator accessory sub complex, transcription regulation and chitin metabolism. These results suggest that SIN3 not only plays a role in regulating the cell cycle but also other processes during development

Tele-Neurorehabilitation During the COVID-19 Pandemic: Implications for Practice in Low- and Middle-Income Countries

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

Identification of genetic suppressors of the Sin3A knockdown wing phenotype.

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

Acute Deletion of Tet2 or Tet3 Transiently Dysregulate Murine Erythropoiesis

The majority of palindromic CpG dinucleotides in mammalian DNA are symmetrically methylated on cytosine (5mC). Erythroid differentiation is associated with replication-dependent genome-wide loss of ~30-50% of all 5mC (1). One potential mechanism of demethylation involves Tet dioxygneases, which oxidize 5 methylcytosine (5mC) to 5-hydroxy-methylcytosine (5hmC), thereby interfering with maintenance methylation by DNMT1 (2). Tet2 and Tet3 are the two major Tet proteins expressed in hematopoietic cells. Tet2 is one of the most commonly mutated genes in hematological malignancies. Germline deletion of Tet2 results in increased hematopoietic stem cell self-renewal, erythroid and myeloid hyperplasia and myeloid and lymphoid malignancies (3, 4). Germline deletion of Tet3 is embryonic lethal (5). Here we investigated the potential role of Tet2 and Tet3 in the global loss of DNA methylation during erythroid differentiation, using mouse genetic models. We bred Tet2fl/fl and Tet3fl/fl mice onto the Rosa26-CreERT2 background, enabling acute deletion in vivo of either Tet2, Tet3 or both genes in adult and fetal mice. Within 4 to 10 days of deletion, we noted a rapid decline in total bone marrow cellularity in all genotypes; bone-marrow erythroblasts decreased to 15% of control value in Tet2-deleted (Tet2del) mice (p<0.0001), and to 43% (p=0.05) and 20% (p<0.0001) of controls in the Tet3 del and Tet2/Tet3 double deleted mice (DKO), respectively. These findings were associated with decreased reticulocyte counts in peripheral blood, and a decline in hematocrit, in Tet2del (36% vs. 46% in controls, p<0.004) and the DKO (31%, p=0.03). Bone-marrow CFU-e progenitors, but not BFU-e progenitors, also decreased in number. These losses partially improved over the next 2 to 4 weeks in mice deleted for either Tet2 or Tet3, but not in the DKO mice, in which anemia persisted. Megakaryocyte CFU-Mk progenitors increase in the DKO but are unaffected in the single deletions. Lymphoid lineage cells (CD4+, CD8+ and CD19+) showed similar transient losses, but the numbers of granylocytic and monocytic progenitors in the bone marrow was not affected. Similarly, fetal liver cell number decreased in all genotypes within 4 days of deletion, compared with controls, in all genotypes, and most severely in the DKO. We used three approaches to determine the potential effect of Tet proteins on erythroid DNA demethylation: Mass spectrometry, to measure global levels of 5mC and 5hmC in fetal liver erythroblasts; 5hMe-DIP-seq (5hyrdoxymethyl-DNA immune precipitation- sequencing), to determine the genomic distribution of hydroxymethylation in erythroblasts; and pyrosequencing for DNA methylation/hydroxymethylation at specific genomic loci including repetitive LINE_1 elements. We found that 5hmC is highly enriched in previously identified erythroid enhancers. Tet2 accelerates, but is not essential, for DNA demethylation of specific erythroid enhancers. Neither Tet2 nor Tet3 are required for global DNA demethylation. Taken together, we conclude that Tet2 and Tet3 are required during erythropoiesis, where they play partially redundant roles, possibly contributing to the changing chromatin environment during activation of erythroid terminal differentiation. Their acute deletion leads to transient loss of erythroblast viability and to anemia, but this is followed by a process of adaptation and chronically compensated erythropoiesis. These results raise the possibility that the adaptation required for the rapid partial recovery in the erythroid and lymphoid lineages following acute Tet2 loss may contribute, over the long term, to the development of myeloid and lymphoid malignancies. 1. J. R. Shearstone et al., Global DNA demethylation during mouse erythropoiesis in vivo. Science334, 799-802 (2011). 2. M. Ko et al., Impaired hydroxylation of 5-methylcytosine in myeloid cancers with mutant TET2. Nature468, 839-843 (2010). 3. M. Ko et al., TET proteins and 5-methylcytosine oxidation in hematological cancers. Immunol Rev263, 6-21 (2015). 4. J. An et al., Acute loss of TET function results in aggressive myeloid cancer in mice. Nature communications6, 10071 (2015). 5. T. P. Gu et al., The role of Tet3 DNA dioxygenase in epigenetic reprogramming by oocytes. Nature477, 606-610 (2011). No relevant conflicts of interest to declare

Immune reconstitution syndrome following initiation of antiretroviral therapy in a patient with HIV infection and multidrug-resistant tuberculosis

Paradoxical exacerbation of the signs and symptoms of tuberculosis may occur not only after antituberculosis therapy, but also soon after the initiation of a potent combination of antiretroviral drugs in human immunodeficiency virus (HIV) serpositive patients with tuberculosis. We report a case of immune reconstitution syndrome in response to antiretroviral therapy in a HIV-positive patient on antituberculosis therapy for multidrug-resistant tuberculosis

Multiple genes that reside along the third chromosome are required for normal wing morphology.

<p>Images of wings from progeny of <i>Ser-GAL4</i> X <i>UAS-RNAi</i> of the indicated gene. For each of these genes, the wing phenotype of the double knockdown was the same as for the single gene knockdown. In cases where the phenotype was variable in the population, multiple representative images are shown.</p

Wing development is sensitive to reduced expression of cell cycle regulators.

<p>Images of representative wings from progeny of <i>Ser-GAL4</i> X <i>UAS-RNAi</i> of the indicated gene (left panels). For each of these genes, the wing phenotype of the double knockdown was the same as for the single gene knockdown except where noted (right panels). For <i>cdc2c</i>, images representing the variable phenotypes in the population are shown.</p

Two components of the Mediator accessory kinase module are important for wing morphology.

<p>Images of representative wings from progeny of <i>Ser-GAL4</i> X <i>UAS-RNAi</i> of the indicated gene. For <i>CycC</i>, the wing phenotype of the double knockdown was the same as for the single gene knockdown. The phenotype of the single and double knockdown phenotype with <i>kto</i> is shown.</p

Genes involved in negative regulation of the Wnt pathway genetically interact with <i>Sin3A</i>.

a<p>SIN3 KD I and II/<i>CyO-Ras</i> females were crossed to males carrying an RNAi or loss of function (LOF) allele for the indicated gene.</p>b<p>The percentage of straight winged flies in the progeny of the cross that are knocked down for <i>Sin3A</i> and for the indicated gene is given. Results are an average of three trials. n>100. Standard deviation is indicated.</p>c<p>Flies had a wing phenotype that was neither straight nor curved.</p><p>n.t., not tested.</p