TRIPLET REPEAT-CONTAINING RIBOSOMAL-PROTEIN L14 GENE IN IMMORTALIZED HUMAN ENDOTHELIAL-CELL LINE (T-HUE4)

A cDNA encoding human 60S ribosomal subunit protein L14 (hRL14) was is olated from a human immortal endothelial cell line, t-HUE4. This cell line was established via a series of cell lines cultured in a serum-fr ee and a protein-free medium, and a directional cDNA library has been constructed and screened in search for the genes modulating protein sy nthesis machinery in cell proliferation. A putative full-length clone with an open reading frame of 220 amino acids; predicted molecular wei ght of 23.6 kDa. A significant identity for hRL14 was observed with ra t RL14 (85% identity), with exception of COOH-terminal region, but not with any eukaryote amino acid sequences so far deposited to database. The typical features of ribosomal proteins were observed in hRL14, as seen in nuclear targeting sequences necessary for the transport from cytoplasm to nucleolus, a bZIP like (basic region-leucine zipper) elem ent for the binding to rRNA, and the internal repeat sequences; the pe ntapeptide QKA(A/S)X The COOH-terminal region of the transcripts conta ined fifteen triplet repeats (GCT; alanine) at nucleotide 465 to 509, which is significantly expanded compared to the rat RL14. However, the repeat number was all the same among the normal human endothelial cel l line and the cell Lines established in the course of t-HUE4 establis hment. A single band with about 800 bases was identified by Northern b lot analysis without tissue specificity. This GCT repeat was found to be one of the longest uninterrupted repeats in a coding sequence, whic h were associated with the highest degree of polymorphism. (C) 1998 Ac ademic Press.