POLR2G

POLR2G Full Name

polymerase (RNA) II (DNA directed) polypeptide G

POLR2G Introduction

POLR2G, widely recognized in structural biology as RPB7, is an indispensable core subunit of RNA polymerase II (Pol II). Pol II is the quintessential eukaryotic enzyme exclusively responsible for the transcription of all protein-coding genes into messenger RNAs (mRNAs). Structurally, POLR2G tightly associates with the RPB4 subunit (POLR2D) to form a prominent heterodimeric subcomplex that protrudes uniquely from the main twelve-subunit Pol II core. This Rpb4/7 stalk is absolutely critical for the initial stages of transcription; it actively bridges the polymerase with various general transcription factors at the gene promoter, firmly anchoring the DNA template to initiate mRNA synthesis. Furthermore, POLR2G physically couples the transcription machinery to downstream mRNA processing and export pathways, seamlessly ensuring that newly transcribed mRNAs are capped, properly packaged, and efficiently exported to the cytoplasm for translation.

Figure 1. Multifunction of Rpb7 in gene expression. (Source: Qiu Z, et al. 2017)

In the clinical landscape, the strict regulation of POLR2G is frequently hijacked during oncogenesis. To sustain their explosive, uncontrolled proliferation, highly aggressive cancer cells require an astronomical amount of proteins, fundamentally relying on massive global mRNA hyper-transcription. Consequently, POLR2G is robustly overexpressed in a variety of deadly solid tumors, most notably hepatocellular carcinoma and advanced breast cancers. This pathological overexpression stabilizes the Pol II complex globally, supercharging the transcription of critical oncogenes and metabolic drivers. High levels of POLR2G clinically correlate with profound tumor aggressiveness, metastasis, and heavily diminished patient survival. Because it acts as an overarching accelerator for oncogenic transcription, targeting the structural interactions of POLR2G is being actively investigated as a disruptive strategy to globally crash the hyperactive transcriptional networks within cancer cells.

Alternate Names for POLR2G

POLR2G; polymerase (RNA) II (DNA directed) polypeptide G; DNA-directed RNA polymerase II subunit RPB7; hRPB19; hsRPB7; RPB7; RNA polymerase II subunit B7; RNA polymerase II 19 kDa subunit; RNA polymerase II seventh subunit; DNA-directed RNA polymerase II subunit G

• 1. Yao F, et al. Single-Cell RNA Sequencing Reveals the Role of Phosphorylation-Related Genes in Hepatocellular Carcinoma Stem Cells. Front Cell Dev Biol. 2022 Jan 4;9:734287.
  2. Qiu Z, et al. Improving Saccharomyces cerevisiae ethanol production and tolerance via RNA polymerase II subunit Rpb7. Biotechnol Biofuels. 2017 May 15;10:125.