O-GlcNAcylation of boundary element associated factor (BEAF 32) in Drosophila melanogaster correlates with active histone marks at the promoters of its target genes

Abstract

Boundary Element-Associated Factor 32 (BEAF 32) is a sequence specific DNA binding protein involved in functioning of chromatin domain boundaries in Drosophila. Several studies also show it to be involved in transcriptional regulation of a large number of genes, many of which are annotated to have cell cycle, development and differentiation related function. Since post-translational modifications (PTMs) of proteins add to their functional capacity, we investigated the PTMs on BEAF 32. The protein is known to be phosphorylated and O-GlcNAcylated. We mapped O-GlcNAc site at T91 of BEAF 32 and showed that it is linked to the deposition of active histone (H3K4me3) marks at transcription start site (TSS) of associated genes. Its role as a boundary associated factor, however, does not depend on this modification. Our study shows that by virtue of O-GlcNAcylation, BEAF 32 is linked to epigenetic mechanisms that activate a subset of associated genes.

Biochemical Deconstruction and Reconstruction of Nuclear Matrix Reveals the Layers of Nuclear Organization

“…In the absence of the putative NMTS, the protein remains nuclear but changes its subnuclear compartment, also changing its solubility. In WT proteins, the solubility or scaffold association of architectural proteins could be regulated by PTMs, which, in the case of Beaf32, are found enriched directly on the NMTS patch ( 92 ). Our dataset can be a useful resource to examine such regulation through cell’s organizational control of protein solubility.…”

The Drosophila BEAF insulator protein interacts with the polybromo subunit of the PBAP chromatin remodeling complex

“…This is consistent with our Y2H results that we interpret as indicating the interaction is weak or requires a specific condition such as an unusual conformation or posttranslational modification of 1 or both interacting surfaces. BEAF is known to be phosphorylated and glycosylated ( Hart et al 1997 ; De et al 2018 ), although whether this happens in yeast is unknown. In addition to gene regulation, PBAP has been implicated in insulator activity ( Nakayama et al 2012 ).…”

Demystifying the O-GlcNAc Code: A Systems View

“…229 Boundary element associated factor (BEAF 32) is also O-GlcNAcylated (on T91), which is linked to the deposition of active histone (H3K4me3) marks at transcription start site of associated genes. 241 Moreover, O-GlcNAcylation of BEAF 32 is found to be present in dividing and/or differentiating tissue but is absent in an already differentiated tissue, suggesting a role of O-GlcNAcylated BEAF 32 in cell division/differentiation. OGT/Sxc-mediated O-GlcNAcylation of homeodomain-interacting protein kinase (HIPK) promotes its protein stability, inducing tumor-like tissue growth abnormalities in Drosophila.…”

“…In the absence of O-GlcNAcylation (e.g., in sxc mutants), Ph forms large protein aggregates and cannot form into functioning assemblies with Polycomb response elements, leading to homeotic defects . Boundary element associated factor (BEAF 32) is also O-GlcNAcylated (on T91), which is linked to the deposition of active histone (H3K4me3) marks at transcription start site of associated genes . Moreover, O-GlcNAcylation of BEAF 32 is found to be present in dividing and/or differentiating tissue but is absent in an already differentiated tissue, suggesting a role of O-GlcNAcylated BEAF 32 in cell division/differentiation.…”