Cloning and characterization of a novel sequence-specific DNA-binding protein recognizing the negative regulatory element (NRE) region of the HIV-1 long terminal repeat.

The present studies describe the isolation of a murine cDNA clone that encodes a novel DNA-binding protein recognizing the negative regulatory element (NRE) region of the HIV-1 long terminal repeat (LTR). This cDNA expresses a truncated protein with a functional DNA-binding domain, which is rich in glutamine/proline and serine/threonine, a characteristic of a majority of sequence-specific DNA-binding proteins and transcriptional factors. The cDNA hybridizes to a single-copy gene that is expressed as an approx. 4.2-kb mRNA in a variety of murine and human cell types, implying that this gene is expressed in an ubiquitous fashion. The NRE region has been reported to down-regulate LTR-directed gene expression [Rosen et al., Cell 41 (1985) 813-823]. This is the first sequence-specific DNA-binding protein reported to recognize the NRE region.