HGNC Approved Gene Symbol: TCEAL7
Cytogenetic location: Xq22.2 Genomic coordinates (GRCh38): X:103,330,239-103,332,326 (from NCBI)
By EST database analysis of a sequence previously identified as a downregulated gene in 3 of 4 suppression subtraction libraries of primary ovarian tumors against normal ovarian epithelial cell brushings, followed by PCR, Chien et al. (2005) cloned TCEAL7. The deduced 100-amino acid protein has a coiled-coil domain. TCEAL7 shares amino acid similarity with TCEAL1 (300237), TCEAL6, and NGFRAP1 (300361).
Chien et al. (2005) showed that overexpression of TCEAL7 in ovarian cancer cells induced apoptosis. RT-PCR analysis detected expression in normal ovarian epithelial cells but demonstrated loss of expression in ovarian cancer cell lines and primary tumors, confirming downregulation in ovarian tumors. Studies with 5-aza-2-prime-deoxycytidine demonstrated a dose-dependent increase in TCEAL7 expression. The authors concluded that methylation of a CpG SmaI site plays a role in controlling TCEAL7 expression and activation in primary ovarian tumors. Chien et al. (2005) stated that there was no evidence for loss of heterozygosity, consistent with the hypothesis that the TCEAL7 locus displays X inactivation and that tumor-related epigenetic silencing inactivated the active allele.
Chien et al. (2005) determined that the TCEAL7 gene contains 3 exons with the entire open reading frame contained in exon 3.
By database analysis, Chien et al. (2005) mapped the TCEAL7 gene to chromosome Xq22.1-q22.3, where it lies 24 kb and 42 kb proximal to TCEAL6 and NGFRAP1, respectively.
Chien, J., Staub, J., Avula, R., Zhang, H., Liu, W., Hartmann, L. C., Kaufmann, S. H., Smith, D. I., Shridhar, V. Epigenetic silencing of TCEAL7 (Bex4) in ovarian cancer. Oncogene 24: 5089-5100, 2005. [PubMed: 15870691] [Full Text: https://doi.org/10.1038/sj.onc.1208700]