Alternative titles; symbols
HGNC Approved Gene Symbol: GTF3A
Cytogenetic location: 13q12.2 Genomic coordinates (GRCh38) : 13:27,424,619-27,435,823 (from NCBI)
The first transcription factor to be identified in eukaryotes was TFIIIA (GTF3A) from Xenopus laevis (Engelke et al., 1980). It is a developmentally regulated protein and is involved in the assembly of active chromatin. The Xenopus gene, termed a C2H2-type zinc finger, has 9 tandem repeats of approximately 30 amino acids each. Each repeat contains a canonical zinc finger, i.e., 2 conserved cysteine residues and 2 conserved histidine residues coordinated by a central zinc atom (Miller et al., 1985). GTF3A was, in fact, the first zinc finger protein characterized. GTF3A is required for RNA polymerase III-mediated transcription of the 5S RNA genes (180420) and binds to both DNA and RNA. Drew et al. (1995) noted that zinc fingers 1-3 bind to an internal control region of the 5S RNA gene and fingers 4-7 are required for binding 5S RNA. The latter results in the formation of 7S ribonucleoprotein particles that stabilize 5S RNA in the frog oocyte and which are required for the rapid growth of the early developing embryo. Zinc fingers 7-9 are involved in protein-protein interactions which leads to transcriptional activation.
The human homolog of GTF3A was purified and characterized by Moorefield and Roeder (1994) and cloned by Drew et al. (1995). The authors identified a partial cDNA with a 363-amino acid open reading frame (ORF) from a human brain library by hybridizing with degenerate oligomer probes. The predicted protein is 57% identical to the Xenopus gene and contains the expected 9 C2H2-type zinc fingers. Northern blots showed that the RNA is expressed in human ovary and human neuronal cell lines.
Arakawa et al. (1995) also reported the cloning of the same cDNA but they obtained a complete 423-amino acid ORF. They noted that zinc finger domains of the predicted protein resembled those in the Wilms tumor protein (607102), the transcriptional repressor YY1 (600013), and the Myc-associated zinc finger protein MAZ (600999).
Arakawa et al. (1995) mapped the GTF3A gene to chromosome 13q12.3-q13.1 by fluorescence in situ hybridization.
Arakawa, H., Nagase, H., Hayashi, N., Ogawa, M., Nagata, M., Fujiwara, T., Takahashi, E., Shin, S., Nakamura, Y. Molecular cloning, characterization, and chromosomal mapping of a novel human gene (GTF3A) that is highly homologous to Xenopus transcription factor IIIA. Cytogenet. Cell Genet. 70: 235-238, 1995. [PubMed: 7789179] [Full Text: https://doi.org/10.1159/000134041]
Drew, P. D., Nagle, J. W., Canning, R. D., Ozato, K., Biddison, W. E., Becker, K. G. Cloning and expression analysis of a human cDNA homologous to Xenopus TFIIIA. Gene 159: 215-218, 1995. [PubMed: 7622052] [Full Text: https://doi.org/10.1016/0378-1119(95)00145-v]
Engelke, D. R., Ng, S.-Y., Shastry, B. S., Roeder, R. G. Specific interaction of a purified transcription factor with an internal control region of 5S RNA genes. Cell 19: 717-728, 1980. [PubMed: 6153931] [Full Text: https://doi.org/10.1016/s0092-8674(80)80048-1]
Miller, J., McLachlan, A. D., Klug, A. Repetitive zinc-binding domains in the protein transcription factor IIIA from xenopus oocytes. EMBO J. 4: 1609-1614, 1985. [PubMed: 4040853] [Full Text: https://doi.org/10.1002/j.1460-2075.1985.tb03825.x]
Moorefield, B., Roeder, R. G. Purification and characterization of human transcription factor IIIA. J. Biol. Chem. 269: 20857-20865, 1994. [PubMed: 8063702]