RNA polymerase I subunit B (POLR1B)

RNA polymerase I subunit B (POLR1B) is the second largest subunit of the multi-protein RNA polymerase I complex, a key enzyme responsible for the transcription of ribosomal RNA (rRNA) genes, which is the initial step in ribosome biogenesis[1][3][5]. POLR1B works together with other core subunits (notably POLR1A and RPA12) in the nucleolus to catalyze the synthesis of the 47S precursor rRNA using ribonucleoside triphosphates and a DNA template[1]. This activity drives protein synthesis and supports cell proliferation and growth[1][3]. Highly regulated, POLR1B—and the larger Pol I complex—is upregulated in cancer and certain stem cell populations, and its dysfunction through mutation or altered expression is implicated in developmental syndromes (e.g., Treacher Collins syndrome), ribosome-related pathologies (ribosomopathies), and aging[3][4][5][6]. POLR1B and other Pol I subunits are emerging targets for anticancer therapy, with specific inhibitors such as BMH-21 and CX-5461 in clinical development[2][4][6].

Other names

DNA-directed RNA polymerase I subunit RPA2RNA polymerase I subunit 2RPA135Rpo1-2FLJ21921FLJ10816RPA2A135TCS4DNA-directed RNA polymerase I 135 kDa polypeptidepolymerase (RNA) I polypeptide Bpolymerase (RNA) I subunit B

Transcription inhibition (small molecule inhibitors, e.g. BMH-21 and CX-5461, block initiation, elongation, or cause degradation of POLR1B and associated subunits)