Abstract
A quail cell line (QT6-c) was co-transfected with pTEX vector expressing RNA complementary to chicken integrin β1 subunit mRNA (Anti-Int) and pRSV neo vector by a calcium phosphate method. Transfectants showing reduced expression of quail integrin β1 subunit were selected with an immunoblot assay, and a few positive clones were examined in detail. Northern blot and immunoblot analyses revealed that the Anti-Int caused a clear reduction of the transcript encoding integrin β1 subunit depending on culture conditions. The number of cell surface integrins also decreased in proportion to the decrement of the total amount of integrin β1 subunits. When one transfectant (QA23)was cultured in a serum-free medium, cell shape changed from fibroblast-like to neuron-like morphology accompanied by a low growth rate, and the cells did not form focal contact on fibronectin. A similar morphological change occurred in QT6-c cells when the cells were infected with Rous Sarcoma virus, which could produce the Anti-Int. The QA23 cells did not attach to fibronectin as efficiently as did the original QT6-c cells. These data suggest that reduced expression of integrin β1 subunit affects cell growth as well as cell morphology by disordering the interaction between integrins and matrix proteins and/or cytoplasmic proteins.
