TY - JOUR

T1 - The expression and properties of polyoma virus middle-T antigen in simian cells

AU - Belsham, Graham J.

AU - Ely, Barry K.

AU - Smith, Alan E.

N1 - Funding Information: We thank Mr. J. Brock and the Photography Department at N.I.M.R. and Mrs. P. Thomas at A.V.R.I. for their assistancei n the preparation of this manuscript. We also acknowledge the gifts of monoclonal antibodies from Dr. B.E. Griffin and Dr. G. Walter and plasmids from Dr. R. Kamen and Dr. C. Tyndall. G.J.B. gratefully acknowledges the support of a Medical Research Council Training Fellowship.

PY - 1986/2

Y1 - 1986/2

N2 - SV40 late replacement vectors containing the polyoma middle-T coding sequences have been constructed. Mixed hybrid virus stocks have been obtained through complementation with a defective SV40 helper genome (dl 1055) following DNA transfection into CV-1 cells. Middle-T antigen is expressed in the infected simian cells at about 5-10 fold higher levels than in polyoma virus-infected mouse cells and has the pp60c-sec-associated tyrosine-specific protein kinase activity in vitro. However, the 'specific activity' of the kinase in extracts of the infected CV-1 cells is lower than that observed in polyoma infected 3T6 cell extracts. The half-life of middle-T antigen in the CV-1 cells is about 4 h but the in vitro kinase activity associated with middle-T has a half-life of at least 8 h and hence appears to be stabilized. The in vivo phosphorylated species of middle-T has been shown by sucrose gradient analyses to be largely distinct from the middle-T with associated protein kinase activity in vitro.

AB - SV40 late replacement vectors containing the polyoma middle-T coding sequences have been constructed. Mixed hybrid virus stocks have been obtained through complementation with a defective SV40 helper genome (dl 1055) following DNA transfection into CV-1 cells. Middle-T antigen is expressed in the infected simian cells at about 5-10 fold higher levels than in polyoma virus-infected mouse cells and has the pp60c-sec-associated tyrosine-specific protein kinase activity in vitro. However, the 'specific activity' of the kinase in extracts of the infected CV-1 cells is lower than that observed in polyoma infected 3T6 cell extracts. The half-life of middle-T antigen in the CV-1 cells is about 4 h but the in vitro kinase activity associated with middle-T has a half-life of at least 8 h and hence appears to be stabilized. The in vivo phosphorylated species of middle-T has been shown by sucrose gradient analyses to be largely distinct from the middle-T with associated protein kinase activity in vitro.

KW - protein phosphorylation

KW - SV40 expression vector

KW - tyrosine-specific protein kinase

UR - http://www.scopus.com/inward/record.url?scp=0022640064&partnerID=8YFLogxK

U2 - 10.1016/0168-1702(86)90039-0

DO - 10.1016/0168-1702(86)90039-0

M3 - Journal article

C2 - 3010597

AN - SCOPUS:0022640064

VL - 4

SP - 157

EP - 177

JO - Virus Research

JF - Virus Research

SN - 0168-1702

IS - 2

ER -