RT Journal Article SR Electronic(1) A1 van Kuppeveld, Frank J. M. A1 van den Hurk, Patrick J. J. C. A1 Schrama, Ina W. J. A1 Galama, Jochem M. D. A1 Melchers, Willem J. G.YR 2002 T1 Trans-complementation of a genetic defect in the coxsackie B3 virus 2B protein JF Journal of General Virology, VO 83 IS 2 SP 341 OP 350 DO https://doi.org/10.1099/0022-1317-83-2-341 PB Microbiology Society, SN 1465-2099, AB The enterovirus 2B protein contains a putative amphipathic α-helix that includes three positively charged and one negatively charged residue. Previously, we observed that replacement of the glutamic acid-40 residue with a lysine residue (mutation 2B-E[40]K) in the amphipathic α-helix of the coxsackie B3 virus 2B protein resulted in a quasi-infectious phenotype. On one occasion, however, transfection of 2B-E[40]K RNA transcripts gave rise to a virus stock in which the mutation was retained. This study was aimed at elucidating the molecular mechanism underlying this observation. Sequence analysis of the viral RNA provided no evidence for a second-site suppression mutation that rescued the defect of the 2B-E[40]K mutation in cis. Therefore, the possibility was considered that the defect caused by the 2B-E[40]K mutation was complemented in trans by viable revertants that had emerged in the virus population. The transfection-derived virus stock indeed contained a small fraction of (pseudo)revertant viruses, carrying the original glutamic acid-40, threonine-40 or asparagine-40, rather than the introduced lysine-40. Consistent with the idea that the 2B-E[40]K virus is unable to grow without the aid of trans-acting wild-type(-like) proteins, only the (pseudo)revertant viruses were able to produce individual plaques. Further support for the idea of trans-rescue was obtained using a genetic complementation assay, which revealed the occurrence of a low level of trans-complementation of the 2B-E[40]K mutation by wild-type virus. This is the first report that provides evidence that a genetic defect in the enterovirus 2B protein can be complemented in trans., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-83-2-341