GTF2H2
Description
The GTF2H2 (general transcription factor IIH subunit 2) is a protein-coding gene located on chromosome 5.
GTF2H2, the gene encoding General transcription factor IIH subunit 2, is located on chromosome 5q13 within a 500 kb inverted duplication region. This region is prone to rearrangements and deletions due to the presence of repetitive elements and multiple genes. Deletion of GTF2H2 may occur alongside deletion of the SMN1 gene in spinal muscular atrophy (SMA) patients, but its contribution to the SMA phenotype remains unclear. GTF2H2 encodes a 44 kDa subunit of the RNA polymerase II transcription initiation factor IIH. This factor is involved in both basal transcription and nucleotide excision repair (NER). While multiple transcript variants have been described for GTF2H2, their full length nature is yet to be determined. Another copy of the GTF2H2 gene exists within the centromeric copy of the duplication, differing by only two or four base pairs from the telomeric copy. However, sequence data for the centromeric copy is currently unavailable.
GTF2H2 is a subunit of the TFIIH complex, which plays a crucial role in both DNA repair and RNA transcription. In DNA repair, specifically nucleotide excision repair (NER), TFIIH acts to open up the DNA around a damaged region, allowing for the removal of the damaged segment and its replacement with a new fragment. In RNA transcription, TFIIH is essential for initiating the process. Once the pre-initiation complex (PIC) is formed, TFIIH is required for opening the promoter region and facilitating the escape of RNA polymerase II from the promoter. This process is regulated by the phosphorylation of the C-terminal tail (CTD) of RNA polymerase II by the CAK module, which is part of the TFIIH complex. The N-terminus of GTF2H2 interacts with and regulates the XPD subunit of TFIIH, while an intact C-terminus is necessary for the successful escape of RNA polymerase II from the promoter.
GTF2H2 is also known as BTF2, BTF2 p44, BTF2P44, T-BTF2P44, TFIIH, p44.
