Enhanced expression of heterotrimeric GTP-binding protein subunits in Zajdela ascitic hepatoma

G protein beta subunit (Gbeta2) is over-expressed in Zajdela ascitic hepatoma (ZAH), a rat ascitic tumour, at mRNA as well as protein levels. Nuclear run-off transcription analysis suggests that the expression of Gbeta2 in ZAH is regulated mainly at transcriptional as well as post-transcriptional levels. Galphai3 is also over-expressed in ZAH. No amplification or any change in the organization of the genes for GBbeta2 or Galphai3 was observed. It is possible that the over-expression of G protein subunits in ZAH could provide proliferative advantage to the cells by virtue of their effects on second messenger systems.