NG2 expression in NG2 glia is regulated by binding of SoxE and bHLH transcription factors to a Cspg4 intronic enhancer

Abstract

NG2 is a type 1 integral membrane glycoprotein encoded by the Cspg4 gene. It is expressed on glial progenitor cells known as NG2 glial cells or oligodendrocyte precursor cells that exist widely throughout the developing and mature central nervous system and vascular mural cells but not on mature oligodendrocytes, astrocytes, microglia, neurons, or neural stem cells. Hence NG2 is widely used as a marker for NG2 glia in the rodent and human. The regulatory elements of the mouse Cspg4 gene and its flanking sequences have been used successfully to target reporter and Cre recombinase to NG2 glia in transgenic mice when used in a large 200-kilobase bacterial artificial chromosome cassette that contained the 38-kilobase Cspg4 gene in the center. Despite the tightly regulated cell type- and stage-specific expression of NG2 in the brain and spinal cord, the mechanisms that regulate its transcription have remained unknown. Here, we describe a 1.45-kb intronic enhancer of the mouse Cspg4 gene that directed transcription of EGFP reporter to NG2 glia but not to pericytes in vitro and in transgenic mice. The 1.45-kb enhancer contained binding sites for SoxE and basic helix-loop-helix transcription factors, and its enhancer activity was augmented cooperatively by these factors, whose respective binding elements were found in close proximity to each other. Mutations in these binding elements abrogated the enhancer activity when tested in the postnatal mouse brain.

Crazy Little Thing Called Sox—New Insights in Oligodendroglial Sox Protein Function

“…Furthermore, the importance of Sox10 for oligodendroglial identity has recently been confirmed, as it was shown to bind and transactivate regulatory regions of NG2, a proteoglycan encoded by the Cspg4 gene and expressed in embryonic and adult OPCs [9,10]. NG2 is expressed shortly after OPC specification immediately following Sox10, is downregulated upon terminal differentiation, and regulates cell adhesion, migration, and proliferation [11,12].…”

NG2/CSPG4, CD146/MCAM and VAP1/AOC3 are regulated by myocardin-related transcription factors in smooth muscle cells

“…Previous work implicated the transcription factors SOX10, ASCL1, and OLIG2 in regulation of CSPG4 transcription in the brain 44 . We therefore tested if these transcription factors were increased by MRTF-A/MKL1.…”

“…Taken together, these findings suggest that regulation of MCAM and AOC3 by MRTF-A/MKL1 involves, in part, a local and KDM3A-dependent epigenetic mechanism. Previous work implicated the transcription factors SOX10, ASCL1, and OLIG2 in regulation of CSPG4 transcription in the brain 44 . We therefore tested if these transcription factors were increased by MRTF-A/MKL1.…”

Novel guanidine compounds inhibit platelet‐derived growth factor receptor alpha transcription and oligodendrocyte precursor cell proliferation

“…In both Oli-neu cells and primary OPCs, the guanidine compounds that decreased Pdgfra transcription also downregulated NG2 (Cspg4) mRNA, which is not surprising, as NG2 is coordinately regulated with PDGFRα during development (McKinnon et al, 1990;Nishiyama et al, 1996b). We recently identified an evolutionarily conserved 1.45-kb enhancer in the first intron of the mouse Cspg4 gene, which is modulated by Sox10 and Olig2 and is sufficient to drive reporter expression in OPCs (Gotoh et al, 2018). NG2 is also highly expressed on proliferative progenitor cells of various lineages and is upregulated in tumors (Hidalgo & Logan, 2017;Stallcup, 2017;Stallcup & Huang, 2008;Yadavilli, Hwang, Packer, & Nazarian, 2016).…”