Analysis of the expression of seven G protein alpha subunit genes in hematopoietic cells.

Various heterotrimeric GTP-binding proteins may have important functions in hematopoietic cells. There has been no comprehensive information, however, regarding their expression in various-lineage hematopoietic cells. In this report, the expression level of seven G protein alpha subunits (Gs alpha, Gi1 alpha, Gi2 alpha, Gi3 alpha, Go alpha-1, Go alpha-2, and Gx alpha) in 13 hematopoietic cell lines were analyzed by Northern blot analysis. Gi1 alpha, Go alpha-1, Go alpha-2, and Gx alpha, were expressed in a limited number of cell lines whereas Gs alpha, Gi2 alpha, and Gi3 alpha were expressed ubiquitously in nearly all cell lines tested. Gi1 alpha was expressed selectively in a pre-T cell line, P30/PHK among lymphoid-lineage cell lines and a myeloblastic cell line, KG-1 among myelomonocytoid cell lines. Go alpha-1 was expressed only in a chronic myelocytic-leukemia cell line, K-562, whereas Go alpha-2 was not expressed in any cell lines tested after ordinary exposure of autoradiography (within 4 days). Gx alpha was expressed abundantly in a rat basophilic-leukemia cell line, RBL-2H3, and expressed in K-562. A barely detectable amount of Gx alpha messenger ribonucleic acid (mRNA) was found after a long exposure of autoradiography in several cell lines with megakaryoblastoid phenotype.