Objectivecolon;Inheritance of a mutant allele of theSDF1gene delays the onset of human immunodeficiency virus type 1 (HIV-1) disease. Because the mutation lies in the 3prime; untranslated region of the gene, it was suggested that this mutation may upregulate transcription of the gene, resulting in more abundant SDF1, which in turn inhibits T-tropic HIV-1 and delays disease onset. This implies that this segment ofSDF1gene contains a negative regulatory element. We directly tested this hypothesis in vitro.Study Designsol;Methodscolon;We cloned the wild-type and the mutantSDF1gene in an HIV-2 gene transfer vector as well as in a baculovirus expression vector. We expressed the cloned genes in human and insect cells in culture and analyzed the abundance of SDF1 RNA by hybridization and protein using antiviral assays.Resultscolon;The abundance of SDF1 RNA synthesized by the mutant clone with the mutation in the 3prime; untranslated region was no different from that synthesized by the wild-type clone in cultured cells. This was the case for both the HIV-2 long terminal repeat (LTR)-directed expression in human cells and baculovirus promoter-directed expression in insect cells. Both clones apparently synthesized SDF1 with equivalent biologic activity. Similar results were obtained for a mutant with the deletion of a GC-rich segment in the 5prime; untranslated region.Conclusionscolon;Mutation of the 3prime; untranslated exon did not affect SDF1 RNA synthesis in vitro. It also did not appear to affect translation of SDF1 RNA. A similar mutational analysis of the 5prime; noncoding exon suggested that this region also did not regulate SDF1 expression.Journal of Human Virology 1999;2:133-138 copy; Lippincott Williams amp; Wilkins, Inc.
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