P. Geck et al., HERPESVIRUS SAIMIRI SMALL RNA AND INTERLEUKIN-4 MESSENGER-RNA AUUUA REPEATS COMPETE FOR SEQUENCE-SPECIFIC FACTORS INCLUDING A NOVEL 70K PROTEIN, Journal of General Virology, 75, 1994, pp. 2293-2301
A highly oncogenic strain of the lymphotropic tumour virus herpesvirus
saimiri (HVS; strain 484-77) expresses four small RNAs (HSUR1 to 4) i
n high copy numbers in transformed T cells. In HSUR1 and HSUR2 the 5'
terminal regions contain conserved AUUUA sequence repeats. The same AU
UUA repeats occur in the 3' non-coding regions of growth factor, lymph
okine and protooncogene mRNAs, and the sequence is involved in rapid m
RNA degradation. We report here that by using a highly specific u.v. c
ross-linking method we identified a novel 70K binding factor with AUUU
A sequence specificity. Non-radiolabelled competition and V8 protease
analysis show that the protein can form a complex with the 3' non-codi
ng region of interleukin-4 mRNA and bind the AUUUA repeats of a HVS sm
all RNA. We also detected an AUUUA-specific minor 32K human protein wi
th the same electrophoretic mobility as a marmoset factor implicated i
n growth factor mRNA destabilization. The findings are consistent with
the hypothesis that the viral small RNAs can compete for factors invo
lved in rapid degradation of growth factor mRNAs and may contribute to
viral oncogenesis.