Id2 and Id4 are not the major negative regulators of oligodendrocyte differentiation during early central nervous system development. Issue 3 (10th December 2021)

• Record Type: Journal Article
• Authors: Huang, Hao; Wu, Huihui; He, Wanjun; Zhou, Fang; Yu, Xianxian; Yi, Min; Du, Junqing; Xie, Binghua; Qiu, Mengsheng
• Is Part Of: Glia. Volume 70:Issue 3(2022)
• Page Start: 590
• Page End: 601
• Publication Date: 2021-12-10
• Subjects: differentiation -- Id2 -- Id4 -- oligodendrocytes -- transcriptional factor; Neuroglia -- Periodicals; Neurology -- Periodicals; 611.0188
• DOI: 10.1002/glia.24126
• Languages: English
• ISSNs: 0894-1491

Abstract

Abstract: Myelin sheathes ensure the rapid conduction of neural impulse and provide nutritional support for neurons. Myelin sheathes are formed by differentiated oligodendrocytes (OLs) in the central nervous system. During OL development, the differentiation of oligodendrocyte progenitor cells (OPCs) into mature OLs is controlled by both positive differentiation factors (drivers) and negative regulatory factors (brakes). Previous studies have suggested Id2 and Id4 as the key negative factors for OL differentiation. However, these conclusions were mainly based on in vitro studies and the reported OL phenotype in Id4 mutants appear to be mild. In this study, we systematically investigated the in vivo function of Id2 and Id4 genes in OL differentiation in their genetic mutants and in embryonic chicken spinal cord. Our results showed that disruption of Id4 has no effect on OL differentiation and maturation, whereas Id2 mutants and Id2 / Id4 compound mutants display a mild and transient precocity of OL differentiation. In agreement with these loss‐of‐function studies, Id2, but not Id4, is weakly expressed in OPCs. Despite their minor roles in OL differentiation, forced expression of Id2 and Id4 in embryonic chicken spinal cords strongly inhibit the differentiation of OPCs. Taken together, our detailed functional and expressional studies strongly suggest that Id2 and Id4 are not the major in vivo repressors of OPC differentiation during animal development, shedding new light on the molecular regulation of early OL development. Main Points: A mild precocious OL differentiation is only observed in Id2 mutants and Id2 / Id4 double mutants, but not in Id4 mutants. Forced expression of Id2 and Id4 in spinal cord strongly inhibits OPC differentiation. Only Id2, but not Id4, is weakly expressed in OPCs in developing CNS.