KAPOSIS-SARCOMA-ASSOCIATED HERPESVIRUS CONTAINS G-PROTEIN-COUPLED RECEPTOR AND CYCLIN-D HOMOLOGS WHICH ARE EXPRESSED IN KAPOSIS-SARCOMA ANDMALIGNANT-LYMPHOMA

A new human herpesvirus was recently identified in all forms of Kaposi 's sarcoma (Kaposi's sarcoma-associated herpesvirus [KSHV] or human he rpesvirus 8), as well as in primary effusion (body cavity-based) lymph omas (PELs). A 12.3-kb-long KSHV clone was obtained from a PEL genomic library. Sequencing of this clone revealed extensive homology and col inearity with the right end of the herpesvirus saimiri (HVS) genome an d more limited homolog to the left end of the Epstein-Barr virus genom e. Four open reading frames (ORFs) were sequenced and characterized; t hese are homologous to the following viral and/or cellular genes: (i) Epstein-Barr virus membrane antigen p140 and HVS p160, (ii) HVS and ce llular type D cyclins, (iii) HVS and cellular G protein-coupled recept ors, and (iv) HVS. Since there is considerable evidence that cyclin D1 and some G protein-coupled receptors contribute to the development of specific cancers, the presence of KSHV homologs of these genes provid es support for a role for KSHV in malignant transformation. All ORFs i dentified are transcribed in PELs and Kaposi's sarcoma tissues, furthe r suggesting an active role for KSHV in these diseases.