Regulation of growth factor induced gene expression by calcium signalling: integrated mRNA and protein expression analysis.

There is considerable indirect evidence that growth factor induced changes in the intracellular concentration of calcium play an important role in the regulation of the mammalian cell cycle. However, the precise mechanism by which this may be achieved remains unclear. Here we show that SKF-96365, an inhibitor of growth factor induced capacitative calcium entry (CCE), inhibits cell cycle progression by preventing entry into S phase. SKF-96365 changes the temporal profile of growth factor induced calcium signalling and recent studies have shown that alterations in the temporal and spatial patterns of calcium signalling can differentially regulate gene expression. We have therefore sought to examine the effect of inhibition of CCE on growth factor induced gene expression during G1. To achieve this we have initiated a combined transcriptomic and proteomic approach to measure CCE regulated gene expression using cDNA arrays and two-dimensional polyacrylamide gel electrophoresis, respectively. The initial results of this on-going analysis are reported here. They reveal that inhibition of CCE influences the expression of 29 genes at the mRNA level and 22 genes at the protein level. We report the identification of the mRNAs whose expression is altered by inhibition of CCE and describe the potential functional significance of some of these changes. The value of integrating a transcriptomic and two-dimensional gel electrophoresis based proteomic approach to studies of gene expression is discussed.