Poly(rC)-binding protein 2 interacts with the oligo(rC) tract of coxsackievirus B3

The human poly(rC)-binding protein (PCBP) 2 is known to interact with enteroviral RNA. Here, the interaction of PCBP2 with RNA target sequences at the 5′ end of the coxsackievirus B3 genome was investigated. Using the electrophoretic mobility shift assay and the yeast three-hybrid system, a short oligo(rC) tract connecting cloverleaf and IRES is demonstrated to contribute to PCBP2 binding. This oligo(rC) tract is conserved among entero- and rhinoviruses. In absence of the viral 3C proteinase, an extended cloverleaf RNA (nt 1–105) containing the oligo(rC) tract interacts with PCBP2 whereas the cloverleaf (nt 1–87) lacking the oligo(rC) tract does not. In the presence of 3C proteinase, cloverleaf RNA (1–87) interacts with PCBP2.