Alternative titles; symbols
HGNC Approved Gene Symbol: GTF2IRD2B
Cytogenetic location: 7q11.23 Genomic coordinates (GRCh38) : 7:75,092,556-75,149,817 (from NCBI)
By searching for genes within the Williams-Beuren syndrome (WBS; 194050) critical region on chromosome 7, Tipney et al. (2004) identified a duplicated region containing at least 2 transcribed GTF2IRD2 genes, which they designated GTF2IRD2A (608899) and GTF2IRD2B, and a pseudogene. They isolated mouse Gtf2ird2 and, by screening a fetal brain cDNA library using the mouse clone, obtained a human cDNA corresponding to GTF2IRD2B. The deduced human GTF2IRD2B protein contains 949 amino acids and has a calculated molecular mass of 107 kD. The N-terminal half of GTF2IRD2B contains a leucine zipper motif, followed by 2 helix-loop-helix motifs (I repeats) that share homology with the TFII-I family of transcription factors (see 601679). The C-terminal half of GTF2IRD2B contains a CHARLIE8 transposable element-like sequence, including 3 transposase-related domains that may be functional, and a BED zinc finger DNA-binding motif. GTF2IRD2B also has 4 N-glycosylation sites and multiple putative phosphorylation sites. The 949-amino acid GTF2IRD2A protein has 6 C-terminal amino acid changes relative to GTF2IRD2B. Northern blot analysis detected a 3.5-kb GTF2IRD2B transcript in all tissues tested, and RT-PCR analysis confirmed ubiquitous expression. Lowest expression was in skin fibroblasts, and fetal tissues showed higher expression than adult tissues. Northern blot and RT-PCR analyses of mouse tissues showed nearly ubiquitous expression of Gtf2ird2. No expression was detected in day-9.5 or -10.5 mouse embryos. Tipney et al. (2004) identified GTF2IRD2 gene orthologs in several mammalian genomes, but not in fly, nematode, or pufferfish genomes.
Tipney et al. (2004) determined that the GTF2IRD2B gene contains 16 exons and spans 57 kb. About 60% of the gene is made up of interspersed repeats, including ALUs and low-complexity repeats, but most of the repeated sequence is a CHARLIE8 DNA element located at the 3-prime end of the coding region. The mouse Gtf2ird2 gene has a similar organization and spans 33.9 kb. About 46.9% of the mouse gene is repeat elements.
By genomic sequence analysis, Tipney et al. (2004) mapped the GTF2IRD2B gene to a duplicated region of chromosome 7q11.23. It is located telomeric to the GTF2IRD2A gene and a GTF2IRD2 pseudogene. By FISH, Tipney et al. (2004) mapped the single-copy mouse Gtf2ird2 gene to a region of chromosome 5G that shows homology of synteny to human chromosome 7q11.23.
Tipney, H. J., Hinsley, T. A., Brass, A., Metcalfe, K., Donnai, D., Tassabehji, M. Isolation and characterization of GTF2IRD2, a novel fusion gene and member of the TFII-I family of transcription factors, deleted in Williams-Beuren syndrome. Europ. J. Hum. Genet. 12: 551-560, 2004. [PubMed: 15100712] [Full Text: https://doi.org/10.1038/sj.ejhg.5201174]