DNA-directed RNA polymerase II subunit M (POLR2M)

DNA-directed RNA polymerase II subunit M (POLR2M) is a metazoan-specific component of a specialized form of RNA polymerase II, termed Pol II(G), which is essential for eukaryotic messenger RNA transcription[1][3]. POLR2M, also known as Gdown1, is tightly and stoichiometrically associated with the RNA polymerase II complex, where it functions predominantly as a negative regulator of transcriptional activation in the absence of the Mediator complex[2][3][4][7][8]. Gdown1 binding occludes the interaction sites for crucial general transcription factors (TFIIF and TFIIB), thereby repressing transcription initiation by preventing preinitiation complex assembly[2]. This repressive action is specifically reversed by the Mediator complex, allowing regulated gene expression in response to signaling[2][4]. While POLR2M/Gdown1 is ubiquitously expressed and implicated in early developmental gene silencing, it is not independently targeted by therapeutic drugs and is not currently classified as a biomarker or direct disease gene[2][3][7]. Its key role lies in the basal mechanisms of RNA polymerase II transcriptional regulation.

Other names

DNA-directed RNA polymerase II subunit GRINL1AGdownGdown1GRINL1AGlutamate receptor-like protein 1AGCOM1GRINL1A downstream protein Gdown4glutamate receptor, ionotropic, N-methyl D-aspartate-like 1Apolymerase (RNA) II (DNA directed) polypeptide Mpolymerase (RNA) II subunit M