Biology subjects

Shaposhnikov, A. V.

Publications and source records attributed to Shaposhnikov, A. V..

2 recordsLinked to original sources

bioRxiv2024

The Enhanced Activation of Innate Immunity in Drosophila S2 Cells by Micrococcus luteus is Mediated by Relish

The IMD and Toll signaling pathways in Drosophila melanogaster mediate the innate immune responses to Gram-negative and Gram-positive bacteria and fungi, respectively. Here we studied the involvement of the NF-{kappa}B transcription factor Relish, which is a mediator of the IMD pathway, in the humoral immune response to the Gram-positive bacteria Micrococcus luteus and Bacillus subtilis and the entomopathogenic fungus Metarhizium anisopliae, using D. melanogaster S2 cells as a model. Activation of Relish proteolysis was observed after S2 cell treatment with the control Gram-negative bacterium Escherichia coli. We found that M. luteus had also a noticeable effect on Relish activation, while B. subtilis and M. anisopliae effects were modest. Activation patterns of the genes encoding predominantly the IMD-pathway-dependent antimicrobial peptides (AMPs) and peptidoglycan recognition proteins (PGRPs), as well as the levels of Relish recruitment to the promoters of the genes, were found to be very similar in S2 cells treated with E. coli or M. luteus but were lower and differed in the case of B. subtilis and M. anisopliae. A Relish knockdown (KD) decreased the induction levels observed for all AMP and some PGRP genes in response to M. luteus treatment and the induction levels observed for several AMP genes after M. anisopliae and B. subtilis exposures. Therefore, our findings suggest that Relish plays a critical role in inducing the humoral immune response in Drosophila S2 cells, contributing primarily to the response against M. luteus and, to a lesser extent, to the responses against B. subtilis and M. anisopliae.

molecular biology↗

bioRxiv2020

PBAP chromatin remodeler mediates enhancer-driven transcription inDrosophila

Chromatin remodeler SWI/SNF is an important participant of gene activation acting predominantly by opening chromatin structure on promoters and enhancers. Here we describe its novel mode of action by mediating targeted action of enhancer. We studied functions of two signature subunits of PBAP subfamily, BAP170 and SAYP, in Drosophila. These subunits were stably tethered onto transgene reporter carrying hsp70 core promoter. Tethered subunits mediate transcription of reporter in a pattern prescribed by nearby enhancer in multiple loci throughout the genome, where the reporter construct was located. Both tethered SAYP and BAP170 recruit the whole PBAP complex onto reporter promoter. Studying difference between these subunits, we found that BAP170-dependent transcription is more resistant to depletion of other PBAP subunits, what may imply the principal role of BAP170 in establishing enhancer-dependent transcription. Author SummaryChromatin remodelers are key molecular machines that are responsible for local changes in chromatin structure in the nucleus. However, their functions in gene expression regulation seem to be broader. We describe the involvement of the SWI/SNF family of remodelers in establishing enhancer-promoter communication, which is apparently independent of its local remodeling activity. Using an artificial tethering of a remodeler on a promoter, we demonstrated that promoters of a certain type become responsive to activation by a nearby enhancer only in the presence of the remodeler, while a remodeler tethering itself is insufficient for gene activation. Thus, our approach helps to uncover novel aspects of molecular interplay on regulatory elements during the gene activation process.

genetics↗