Fealey, Meghan E et al. (2017) International Worm Meeting "Developmental regulation of H3K9me2 and chromatin compaction by C. elegans synMuv B proteins."

Petrella, Lisa N, Strome, Susan, Fealey, Meghan E, Egelhofer, Thea, Rechsteiner, Andreas, Doerger, Ethan

[International Worm Meeting, 2017]

A central question in development is how chromatin is organized and regulated to ensure proper gene expression and cell fate. During early embryo development, before gene expression is globally upregulated, chromatin is found in an open state. As development proceeds and cells differentiate, the genome compacts and becomes organized into open and closed domains. Genes required for a particular fate remain open and poised for transcription factor binding, while genes not needed for that fate are further compacted and sequestered to the nuclear periphery. Although this process is highly regulated, many of the proteins involved in this progression are unknown. Loss of C. elegans synMuv B proteins causes changes in the developmental regulation of chromatin and gene expression. Many synMuv B mutants, including lin-15B, show ectopic expression of germline genes in somatic cells and a high temperature larval arrest (HTA) phenotype. The HTA phenotype is rescued by knockdown of chromatin modifiers, suggesting that synMuv B proteins regulate gene expression programs epigenetically. To investigate ways in which synMuv B proteins may affect chromatin, we performed ChIP-seq analysis of several histone modifications in wild type and synMuv B mutants at 20 deg C and 26 deg C. Intriguingly, lin-15B mutants lose promoter localized H3K9me2 over germline genes in somatic tissues in a temperature independent manner. Typical enrichment of H3K9me2 over gene bodies is not disrupted in these mutants. Promoter localized H3K9me2 is an unstudied pattern for this mark in C. elegans, and the mechanism by which it regulates gene expression is unknown. We investigated if synMuv B proteins function to regulate developmental chromatin compaction. synMuv B mutants display a developmental delay in chromatin compaction that is sensitive to temperature. This delay results in open chromatin during the window when ectopic expression of germline genes in somatic tissues begins. Using temperature shift assays, we found that the crucial developmental time period for the HTA phenotype is the same as the time period when synMuv B mutants display open chromatin. Open chromatin during this period may allow germline genes to be poised for ectopic expression in somatic tissues of synMuv B mutants. Interestingly, the last cells to divide in the intestine are the last cells to adopt compact chromatin, suggesting that the transition to organized chromatin is coupled with differentiation. Understanding synMuv B regulation of promoter enrichment of H3K9me2 and chromatin compaction will help elucidate pathways used to achieve proper gene expression and correct development.

Magoulas GE et al. (2020) Bioorg Chem "Synthesis, biological evaluation and QSAR studies of new thieno[2,3-d]pyrimidin-4(3H)-one derivatives as antimicrobial and antifungal agents."

Sokovic M, Calogeropoulou T, Zoumpoulakis P, Prousis KC, Kritsi E, Magoulas GE, Chondrogianni N, Kalopetridou L, Ciric A, Kouka P

[Bioorg Chem, 2020]

A series of new thieno[2,3-d]pyrimidin-4(3H)-one derivatives were synthesized and evaluated for their activity against four gram-positive and four gram-negative bacterial and eight fungal species. The majority of the compounds exhibited excellent antimicrobial and antifungal activity, being more potent than the control compounds. Compound 22, bearing a m-methoxyphenyl group and an ethylenediamine side chain anchored at C-2 of the thienopyrimidinone core, is the most potent antibacterial compound with broad antimicrobial activity with MIC values in the range of 0.05-0.13mM, being 6 to 15 fold more potent than the controls, streptomycin and ampicillin. Furthermore, compounds 14 and 15 which bear a p-chlorophenyl and m-methoxyphenyl group, respectively, and share a 2-(2-mercaptoethoxy)ethan-1-ol side chain showed the best antifungal activity, being 10-15 times more potent than ketoconazole or bifonazole with MIC values 0.013-0.026 and 0.027mM, respectively. Especially in the case of compound 15 the low MIC values were accompanied by excellent MFC values ranging from 0.056 to 0.058mM. Evaluation of toxicity in vitro on HFL-1 human embryonic primary cells and in vivo in the nematode C. elegans revealed no toxic effects for both compounds 15 and 22 tested at the MIC concentrations. Ligand-based similarity search and molecular docking predicted that the antibacterial activity of analogue 22 is related to inhibition of the topoisomerase II DNA gyrase enzyme and the antifungal activity of compound 15 to CYP51 lanosterol demethylase enzyme. R-Group analysis as a means of computational structure activity relationship tool, highlighted the compounds' crucial pharmacophore features and their impact on the antibacterial and antifungal activity. The presence of a N-methyl piperidine ring fused to the thienopyrimidinone core plays an important role in both activities.