Sequence and phylogeny of HERV-W pol fragments.

A new human endogenous retroviral family (HERV-W) has been described that is related to multiple sclerosis-associated retrovirus (MSRV) sequences that have been identified in particles recovered from monocyte cultures from patients with multiple sclerosis. Using the PCR approach with a human monochromosomal somatic cell hybrid DNA panel, 24 pol fragments of the HERV-W family from chromsomes 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 20, 21, X, and Y were identified and analyzed. They showed a high degree of nucleotide sequence similarity (89.3-91.3%) with that of the HERV-W. Translation of the pol fragments showed no frameshift and termination codon by deletion/insertion or point mutation in some clones: HWP4-1, HWP4-2 from chromosome 4, and HWPX-1 from chromosome X. Phylogenetic analysis of the HERV-W family indicates that the pol fragments have evolved independently among chromosomes or represent separate integration events during primate evolution.