The genetic variability of the human herpesvirus 8 (HHV-8) strains circulating in the populations living in the Maghreb region, an endemic area for HHV-8 and associated Kaposi's sarcoma, remains largely unknown. We have thus analyzed the genetic variation of the complete K1 gene of HHV-8 in a series of 35 viral strains, originating from 28 Moroccan patients with classic, AIDS-associated or iatrogenic Kaposi's sarcoma lesions. All but one of the 35 strains belonged to the large C molecular subtype. Furthermore, high genetic diversity within the C subtype was observed in the 35 sequenced HHV-8 K1 genes, with strains belonging to several and distinct subgroups highly supported from a phylogenetically viewpoint (e.g., C3, C7, C'' and C5). Considering these newly identified Moroccan viral strains in the context of 189 complete K1 genes, we were able to characterized, using the Simplot program, two main groups of recombinant chimeric K1 genes, either intertypic (C5) or intratypic (C7). In addition, the genetic characterization of the host maternal gene pool, through the analyses of mtDNA variation, did not provide evidence for any association between a particular human ethno-geographic background (i.e., North African vs. sub-Saharan African vs. West Eurasian linages) and any HHV-8 strain because both C' and C'' strains were randomly distributed among the different patients' population backgrounds.

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Vitamin D metabolites are able to change plasma calcitonin (CT) levels, but nothing is known about a possible effect at the CT gene level. Here we have investigated the acute effects of 1,25-dihydroxyvitamin D, (1,,D) on the CT biosynthetic activity of thyroid glands from adult rats. Plasma CT levels were significantly increased ( x 2) 1 and 2 h after 1,25-(OH),D, injection in the face of unchanged plasma calcium values. The thyroidal CT content also was unchanged. A 2-fold increase in CT mRNA level measured by dot-blot hybridization occurred 1 and 2 h after 1,25-(OH),D, administration. Expression of CT gene products was examined in the rabbit reticulocyte lysate cell-free translation assay. After polyacrylamide gel electrophoresis, specific immunopr~pitat~ were autoradiographed and quantified by integration. A singie precursor of M, = 15000 could be specifically immunoprecipitated with CT antisera. A 3-4-fold rise in translatable CT mRNA activity was observed 1 and 2 h after 1,25-(OH),D, injection. Thus, parallel changes in CT mRNA level, CT mRNA activity and plasma CT levels were observed in adult female rats after administration of 1,25-(OH),D,. These findings demonstrate for the first time that 1,25-(OH),D, enhanced CT gene expression in the face of unchanged plasma calcium levels.