Genes of kaposi's sarcoma associated herpesvirus

摘要

A human gamma herpesviris genome known as Kaposi sarcoma associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8) is present in virtually all AIDS and non-AIDS Kaposi's sarcoma (KS) lesions, as well as in body cavity based lymphomas (BCBL), Multiple myeloma, and in multicentric Casdeman's disease. Isolation and DNA sequencing of a 17-kb segment encompassing a HHV-8 divergent locus (DL-B) between ORF11 and ORF17 revealed the presence of nine viral ORFs with gene products related to cellular proteins. These include the complete thymidylate synthase (TS) gene and a dihydrofolate reductase (DHFR) gene, four cytokine genes (vIL6, vMIP-1A, vMIP-1B and BCK) that have not previously been found to be encoded by a virus, and a Bcl2 homologue. This region in HHV-8 also contains the T1.1 abundant lytic cycle nuclear RNA gene and encompasses two genes (or exons) encoding proteins with C4HC3 zinc finger domains of the PHD/LAP subtype. The latter are related to the spliced immediatelady IE1 protein of the bovine gamma-2 class herpesvirus BHV-4 and a similar motif found in HVS ORF12. Transcripts form the IE-1A, IE-1B, DHFR, and MIP-1B genes were all detected by Northern blot hybridization analysis in a BCBL cell line at 12-h after induction with butyrate, but were not present before induction, indicating that these are all primarily lytic cycle genes.