USE OF A POLYETHYLENE GLYCOL-PEPTIDE CONJUGATE IN A COMPETITION GEL SHIFT ASSAY FOR SCREENING POTENTIAL ANTAGONISTS OF HIV-1 TAT PROTEIN-BINDING TO TAR RNA

Interference of binding of Tat protein to TAR RNA in HIV-l-infected ce lls may be a useful therapeutic strategy for AIDS. An electrophoretic assay to screen potential low-molecular-weight (<2 kDa) Tat antagonist s has been established. A radiolabeled TAR RNA fragment (Delta TAR) is retarded in mobility when bound by a Tat peptide-polyethylene glycol conjugate (Tat-PEG), which is used in place of the Tat protein. The as say determines the ability of a potential antagonist to compete with T at-PEG for binding to Delta TAR, as measured by interference with the gel shift of Delta TAR. To discriminate between specific and nonspecif ic interactions, the assay is done in the absence or the presence of a 250-fold molar excess of tRNA. (C) 1995 Academic Press, Inc.