CLONING AND CHARACTERIZATION OF THE ENDOGENOUS RETROVIRAL-TRNA(GLU) MULTIGENE FAMILY FROM HUMAN GENOMES OF DIFFERENT RACIAL BACKGROUNDS

An 8.3-kb human endogenous retroviral-tRNA(Glu) (HERV-E)-encoding cDNA clone and a 1.5-kb genomic done were isolated from a Chinese-derived cervical cancer cell line, CC7T, and their sequences determined, The f ormer is a full-length endogenous retroviral cDNA containing correspon ding u(5)-gag-pol-enc-u(3)-r regions. The latter is a partial retrovir al DNA segment, covering the gag and pol genes. Analysis of normal hum an DNA by Southern blot hybridization with three specific HERV-E molec ular DNA probes revealed complex restriction-fragment length polymorph isms (RFLP), implying that the human genome contains diverse proviral structures and dispersed integration sites, The complex patterns were virtually identical between DNAs from African-Americans, Asians and Ca ucasians, with only a few minor variations. The data suggest that thes e proviral sequences were mostly incorporated into the human genome be fore racial divergence and, hence, may serve as markers for distinct c hromosomal sites.