C9ORF135 encodes a membrane protein whose expression is related to pluripotency in human embryonic stem cells

Abstract

Abstract Human embryonic stem cells (hESCs) are a unique population of cells defined by their capacity for self-renewal and pluripotency. Here, we identified a previously uncharacterized gene in hESCs, C9ORF135 , which is sharply downregulated during gastrulation and gametogenesis, along with the pluripotency factors OCT4, SOX2, and NANOG. Human ESCs express two C9ORF135 isoforms, the longer of which encodes a membrane-associated protein, as determined by immunostaining and western blotting of fractionated cell lysates. Moreover, the results of chromatin immunoprecipitation (ChIP), mass spectrometry (MS), and co-immunoprecipitation (co-IP) analyses demonstrated that C9ORF135 expression is regulated by OCT4 and SOX2 and that C9ORF135 interacts with non-muscle myosin IIA and myosin IIB. Collectively, these data indicated that C9ORF135 encodes a membrane-associated protein that may serve as a surface marker for undifferentiated hESCs.