Viral sequence integration into introns of chemokine receptor genes

Viral DNA sequences are able to integrate into the non-coding DNA sections of the genome of human cells which have been infected, either spontaneously or experimentally. We have made a data-base search for integration events of non-endogenous viruses into the introns of chemokine receptor sequences. A BLAST search of all viral DNA sequences, using the intronic sequences as "Query," returned several significant alignments. However, due to the high reiteration rate of the non-coding sequences in the human genome, it became necessary to re-examine the individual alignments to verify whether the virus-flanking intronic sequence was really located in a chemokine receptor intron. We found only one unquestionable event of viral insertion of a section of a long terminal repeat of the murine leukemia virus within the first intron of the CC chemokine receptor 7 gene. Possible biological effects of such an insertion are discussed. Further experimental or clinical research could demonstrate the occurrence of other intronic viral insertions in human chemokine receptor genes.