Identification of a novel gene on chromosome 13 between BRCA-2 and RB-1

METHODS AND RESULTS. By differential display we isolated a new cDNA-fragmen t, named C13, that is downregulated in malignant prostate tissues. Northern hybridization revealed the fragment to be part of 3.0 and 4.4 kb mRNAs. Fl uorescence in situ hybridization, Southern blotting and radiation hybrid ma pping demonstrated a chromosomal localization of C13 on 13q12-14 closest to the SHGC-34125 marker. In the 5% chromosomal environment of C13 we detecte d changes of the allelic status in 13 of 21 prostate cancers. A downregulat ion was detected at the mRNA level in patients with advanced carcinoma. The 3.0 kb full length cDNA clone encodes a protein with an open reading frame of 2,202 bp or 733 amino acids. The corresponding protein contains a putat ive nuclear localization signal, several glutamine clusters and an alpha -h elix-rich domain. By in situ RNA hybridization we could demonstrate the mai nly epithelial expression of the C13 mRNA in prostatic tissue. CONCLUSIONS. The localization of C13 between the tumor suppressor genes BRC A-2 and RB-1, the detected allelic imbalances, the downregulation of its mR NA in some prostatic cancer tissues, the epithelial expression and the desc ribed protein structure suggest that this gene encodes a protein that may h ave turner or metastasis suppressing function in prostate tissue. Prostate 47:91-101, 2001. (C) 2001 Wiley-Liss, Inc.