POLR2B
Description
The POLR2B (RNA polymerase II subunit B) is a protein-coding gene located on chromosome 4.
The POLR2B gene encodes DNA-directed RNA polymerase II subunit RPB2, an enzyme involved in the synthesis of messenger RNA (mRNA) in eukaryotes. This gene produces the second largest subunit of RNA polymerase II, the enzyme responsible for synthesizing mRNA.
The POLR2B gene encodes the second largest subunit of RNA polymerase II (Pol II), a DNA-dependent RNA polymerase that synthesizes messenger RNA (mRNA) precursors and various functional non-coding RNAs. Pol II is essential for transcription, a process that involves three stages: initiation, elongation, and termination. During initiation, Pol II forms a pre-initiation complex (PIC) at DNA promoters, which can be focused-type (containing Inr elements or TATA-boxes) or dispersed-type (containing hypomethylated CpG islands). Once Pol II escapes the promoter, it enters the elongation phase, where RNA is synthesized based on the DNA template. Finally, transcription termination involves releasing the RNA transcript and Pol II from DNA.
POLR2B forms the Pol II active center in collaboration with the largest subunit, POLR2A/RPB1. The POLR2B subunit participates in coordinating a second Mg(2+) ion and provides lysine residues that facilitate Watson-Crick base pairing during nucleotide addition. POLR2B also exhibits 3' to 5' exonuclease activity, allowing it to proofread the nascent RNA transcript and remove misincorporated ribonucleotides by backtracking along the DNA template.
POLR2B is also known as POL2RB, RPB2, hRPB140.
Associated Diseases
- acrocephalosyndactyly
- endometrial cancer
- thyroid gland adenocarcinoma
- low grade glioma
- ovarian cancer
- urinary bladder cancer
