Impaired erythroid-specific gene expression in cAMP-dependent protein kinase-deficient murine erythroleukemia cells

• Published in: The Journal of biological chemistry Vol. 268; no. 27; pp. 20252 - 20258
• Main Author: PILZ, R. B
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 25.09.1993
• Subjects: 5-Aminolevulinate Synthetase - biosynthesis; Acetamides - pharmacology; Aminolevulinic Acid - pharmacology; Animals; Biological and medical sciences; Blotting, Northern; Cell Differentiation - drug effects; Cell Nucleus - metabolism; Ferritins - biosynthesis; Fundamental and applied biological sciences. Psychology; Gene Expression; Genes, myc - drug effects; Globins - biosynthesis; Hematinics - pharmacology; Heme - biosynthesis; Heme - metabolism; Hemin - pharmacology; Hemoglobins - biosynthesis; Hydroxymethylbilane Synthase - biosynthesis; Leukemia, Erythroblastic, Acute - enzymology; Leukemia, Erythroblastic, Acute - metabolism; Leukemia, Experimental - enzymology; Leukemia, Experimental - metabolism; Mice; Molecular and cellular biology; Molecular genetics; Oncogenes - drug effects; Protein Kinases - deficiency; RNA, Messenger - biosynthesis; RNA, Messenger - metabolism; Transcription, Genetic - drug effects; Transfection; Tumor Cells, Cultured; Erythroleukemia; Enzyme; Transferases; Rodentia; Tissue specificity; Gene expression; Cell differentiation; Vertebrata; Mammalia; Cell line; Mouse; Protein kinase; Heme
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(20)80722-4

Murine erythroleukemia cells rendered deficient in cAMP-dependent protein kinase (A-kinase) activity by gene transfection are severely impaired in hexamethylene bisacetamide (HMBA)-induced differentiation (Pilz, R. B., Eigenthaler, M., and Boss, G. R. (1992) J. Biol. Chem. 267, 16161-16167). We now demonstrate that the A-kinase-deficient cells produce hemoglobin normally in response to exogenous hemin and that the heme precursor delta-aminolevulinate (delta-ALA) significantly increases HMBA-induced synthesis of heme and globin chains in these cells; these data suggest that impaired heme synthesis is at least partially responsible for the cells' deficient hemoglobin synthesis. HMBA-induced expression of the erythroid-specific delta-ALA synthetase, porphobilinogen deaminase, and beta-globin mRNAs was less in A-kinase-deficient cells than in parental cells and was reduced in proportion to the cells' residual A-kinase activity; relative transcription rates of these genes were reduced concordantly. Impaired expression of these three erythroid-specific genes was a feature of many independently-derived A-kinase-deficient clones, and normal expression was found in transfectants with normal A-kinase activity. The A-kinase-deficient cells did not exhibit a generalized defect in gene regulation since mRNA expression and transcription rates of H- and L-ferritin, c-myc, c-myb, and several housekeeping enzymes were similar in HMBA-treated parental and A-kinase-deficient cells. Our data suggest that A-kinase may be involved in regulating genes with erythroid-specific promoters and provide further evidence for heme as a regulator of globin chain synthesis.