RT Journal Article SR Electronic(1) A1 Mitchison, Hannah M. A1 Grand, Roger J. A. A1 Byrd, Philip J. A1 Johnson, Gerald D. A1 Parton, Adrian A1 Gallimore, Phillip H.YR 1990 T1 The Expression of the Adenovirus 12 Early Region 1B 19K Protein Using a Recombinant Simian Virus 40 System JF Journal of General Virology, VO 71 IS 8 SP 1713 OP 1722 DO https://doi.org/10.1099/0022-1317-71-8-1713 PB Microbiology Society, SN 1465-2099, AB Using a simian virus 40/adenovirus 12 (Adl2)-recom binant virus, the Ad 12 early region IB (E1B) 19K protein has been produced at high levels after infection of Cos 1 cells. Expression of the 19K polypeptide reaches a maximum at about 48 h post-infection, declining at later times as host cell death occurs. Using two-dimensional isoelectric focusing/SDS-polyacryl- amide gel electrophoresis, we have shown that the Ad 12 E1B protein is a major species following infection of Cos 1 cells with recombinant virus. Two forms of 19K polypeptide can be distinguished following isoelectric focusing. Using subcellular fractionation of infected cells, it was found that a similar distribution of 19K protein occurred after recombinant virus and Ad 12 infection, with the polypeptide being most abundant in nuclear and membranous fractions. Similarly, as in Adl2-infected cells, a certain proportion of the protein is located on the outside surface of the cell after recombinant viral infection. Immuno- histochemical studies suggest that, at early times postinfection, the E1B 19K protein is located in the nuclear membrane, the Golgi apparatus and the endoplasmic reticulum. At later times, it can be seen to have spread to the cytoplasm as well as to the other organelles. These results are discussed in relation to the known functions of the 19K E1B protein., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-71-8-1713