Alternative titles; symbols
HGNC Approved Gene Symbol: TOB2
Cytogenetic location: 22q13.2 Genomic coordinates (GRCh38): 22:41,433,494-41,446,801 (from NCBI)
TOB2 belongs to the TOB (see TOB1; 605523)/BTG1 (109580) family of antiproliferative proteins, which are involved in the regulation of cell cycle progression.
Using RT-PCR-mediated cDNA cloning with primers corresponding to the conserved protein sequence in TOB/BTG1 family members, followed by screening of a Daudi B-cell cDNA library, Ikematsu et al. (1999) cloned a TOB2 cDNA. The deduced 344-amino acid TOB2 polypeptide has a calculated molecular mass of 37 kD. It shares 61% overall sequence homology with the TOB1 protein, and both proteins contain a putative nuclear localization signal in the conserved N-terminal domain. Immunofluorescence analysis revealed localization almost exclusively in the cytoplasm. Northern blot analysis of human adult tissues detected ubiquitous expression of a 4.1-kb transcript, with relatively high expression in skeletal muscle, thymus, and ovary. In situ hybridization in several mouse tissues demonstrated intense hybridization in ovary, with characteristic expression in oocytes. Immunoblot analysis revealed a 43-kD protein.
Ajima et al. (2000) cloned and characterized mouse Tob1, which encodes a 345-amino acid protein that shares 89% sequence identity with its human counterpart. In situ hybridization demonstrated ubiquitous expression in embryo, with highest expression in skeletal muscle.
Using transfection experiments, Ikematsu et al. (1999) found that, like TOB1, TOB2 inhibits cell cycle progression from the G0/G1 to S phases. The N-terminal halves of both TOB1 and TOB2 were found to associate with a human homolog of yeast Caf1 (604913), a component of the CCR4 transcription factor complex that associates with cyclin-dependent kinases.
By FISH, Ikematsu et al. (1999) mapped the TOB2 gene to chromosome 22q13.1-q13.31.
Ajima, R., Ikematsu, N., Ohsugi, M., Yoshida, Y., Yamamoto, T. Cloning and characterization of the mouse tob2 gene. Gene 253: 215-220, 2000. [PubMed: 10940559] [Full Text: https://doi.org/10.1016/s0378-1119(00)00270-5]
Ikematsu, N., Yoshida, Y., Kawamura-Tsuzuku, J., Ohsugi, M., Onda, M., Hirai, M., Fujimoto, J., Yamamoto, T. Tob2, a novel anti-proliferative Tob/BTG1 family member, associates with a component of the CCR4 transcriptional regulatory complex capable of binding cyclin-dependent kinases. Oncogene 18: 7432-7441, 1999. [PubMed: 10602502] [Full Text: https://doi.org/10.1038/sj.onc.1203193]