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Identification of a new cancer/testis gene family, CT47 , among expressed multicopy genes on the human X chromosome
Author(s) -
Chen YaoTseng,
Iseli Christian,
Venditti Charis A.,
Old Lloyd J.,
Simpson Andrew J. G.,
Jongeneel C. Victor
Publication year - 2006
Publication title -
genes, chromosomes and cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.754
H-Index - 119
eISSN - 1098-2264
pISSN - 1045-2257
DOI - 10.1002/gcc.20298
Subject(s) - biology , gene , gene family , genetics , chromosome , gene expression , cancer , microbiology and biotechnology
Cancer/testis (CT) genes are normally expressed in germ cells only, yet are reactivated and expressed in some tumors. Of the approximately 40 CT genes or gene families identified to date, 20 are on the X chromosome and are present as multigene families, many with highly conserved members. This indicates that novel CT gene families may be identified by detecting duplicated expressed genes on chromosome X. By searching for transcript clusters that map to multiple locations on the chromosome, followed by in silico analysis of their gene expression profiles, we identified five novel gene families with testis‐specific expression and >98% sequence identity among family members. The expression of these genes in normal tissues and various tumor cell lines and specimens was evaluated by qualitative and quantitative RT‐PCR, and a novel CT gene family with at least 13 copies was identified on Xq24, designated as CT47 . mRNA expression of CT47 was found mainly in the testes, with weak expression in the placenta. Brain tissue was the only positive somatic tissue tested, with an estimated CT47 transcript level 0.09% of that found in testis. Among the tumor specimens tested, CT47 expression was found in ∼15% of lung cancer and esophageal cancer specimens, but not in colorectal cancer or breast cancer. The putative CT47 protein consists of 288 amino acid residues, with a C‐terminus rich in alanine and glutamic acid. The only species other than human in which a gene homologous to CT47 has been detected is the chimpanzee, with the predicted protein showing ∼80% identity in its carboxy terminal region. © 2005 Wiley‐Liss, Inc.