Stable expression of VLA-4 and increased maturation of the beta 1-integrin precursor after transfection of CHO cells with alpha 4m cDNA.
A full-length cDNA coding for the murine alpha 4 integrin subunit (alpha 4m) was transfected into CHO-K1 cells and cell lines that expressed VLA-4 at their surface as a result of the association of transfected alpha 4m with endogenous hamster beta 1 were selected. Functionality of the expressed alpha 4m beta 1 was shown by adhesion assays on VCAM-1 and antibody (anti-VCAM-1) inhibition. Pulse chase experiments indicated that transfection of the murine alpha 4 cDNA into CHO cells led to an increase in maturation and a decrease in degradation of the beta 1 precursor subunit compared to control CHO-K1 cells. This was supported by FACS analysis, using an anti-hamster beta 1 monoclonal antibody, which showed that more beta 1 subunit was expressed at the surface of these stably transfected alpha 4m expressing cells. These results support the hypothesis that degradation of precursor beta 1 is at least partly determined by the quantity of alpha subunits available intracellulary for heterodimer formation.
Jaspers
M
M
Center for Human Genetics, University of Leuven, Belgium.
de Meirsman
C
C
Schollen
E
E
Vekemans
S
S
Cassiman
J J
JJ
D000818:Animals; D016466:CHO Cells; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D006224:Cricetinae; D018076:DNA, Complementary; D039441:Integrin alpha4; D019012:Integrin beta1; D016023:Integrins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D011498:Protein Precursors / Q000096:biosynthesis / Q000378:metabolism; D016029:Receptors, Very Late Antigen / Q000096:biosynthesis*; D014162:Transfection; D019010:Vascular Cell Adhesion Molecule-1
D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; D019012:Integrin beta1; D016023:Integrins; D011498:Protein Precursors; D016029:Receptors, Very Late Antigen; D019010:Vascular Cell Adhesion Molecule-1; D039441:Integrin alpha4