Specific binding of host cell proteins to the 3'-terminal stem-loop structure of rubella virus negative-strand RNA

Abstract

At the 5' end of the rubella virus genomic RNA, there are sequences that can form a potentially stable stem-loop (SL) structure. The complementary negative-strand equivalent of the 5'-end SL structure of positive-strand rubella virus RNA [5' (+) SL structure] is thought to serve as a promoter for the initiation of positive-strand synthesis. We screened the negative-strand equivalent of the 5' (+) SL structure (64 nucleotides) and the adjacent region of the negative-strand RNA for their ability to bind to host cell proteins. Specific binding to the 64-nucleotide-long potential SL structure of three cytosolic proteins with relative molecular masses of 97, 79, and 56 kDa was observed by UV-induced covalent cross-linking. There was a significant increase in the binding of the 97-kDa protein from cells upon infection with rubella virus. Altering the SL structure by deleting sequences in either one of the two potential loops abolished the binding interaction. The 56-kDa protein also appeared to bind specifically to an SL derived from the 3' end of positive-strand RNA. The 3'-terminal structure of rubella virus negative-strand RNA shared the same protein-binding activity with similar structures in alphaviruses, such as Sindbis virus and eastern equine encephalitis virus. A possible role for the host proteins in the replication of rubella virus and alphaviruses is discussed.

Novel packages of viral and self-antigens are generated during apoptosis.

“…Once tolerance is broken, the autoantibody response may be driven by p53 alone (7). It is therefore of great interest that calreticulin, an ER autoantigen in SLE, has recently been shown to form complexes with rubella and al- phaviruses during viral replication (16,17). The ability of complexes of these molecules to break tolerance to calreticulin remains to be addressed.…”

Cis-acting RNA elements in human and animal plus-strand RNA viruses

“…The complementary negative strand equivalent of the 5′ SL structure of RV [3′(−)SL] was found to bind specifically three cellular proteins (p56, p79, p97). Altering the SL structure in either one of the two predicted loops has abolished the binding interaction [189].…”

5′- and 3′-noncoding regions in flavivirus RNA

“…Similar specificity has been reported for other viral systems. For example, one of the cellular proteins that binds rubella virus RNA appears to have specific affinity for both minus-and plus-sense SL structures at the 3 0 -termini of the respective RNAs (Nakhasi et al, 1991). Blackwell and Brinton (1997) subsequently identified the 56-kDa protein that bound the WN 3 0 SL in BHK cell lysates as the translation elongation factor, eF-1.…”