RNA recognition motif in negative elongation factor E (NELF-E) and similar proteins
This subfamily corresponds to the RRM of NELF-E, also termed RNA-binding protein RD. NELF-E is the RNA-binding subunit of cellular negative transcription elongation factor NELF (negative elongation factor) involved in transcriptional regulation of HIV-1 by binding to the stem of the viral transactivation-response element (TAR) RNA which is synthesized by cellular RNA polymerase II at the viral long terminal repeat. NELF is a heterotetrameric protein consisting of NELF A, B, C or the splice variant D, and E. NELF-E contains an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). It plays a role in the control of HIV transcription by binding to TAR RNA. In addition, NELF-E is associated with the NELF-B subunit, probably via a leucine zipper motif.