Differential synthesis of beta-major and beta-minor globin proteins in murine erythroleukemia cells is regulated at the transcriptional level.
We compared the transcription and translation of globin genes in three mouse erythroleukemia cell lines under different conditions in which there is differential expression of beta-major (beta ma) and beta-minor (beta mi). Transcription was measured by pulse labeling of whole cell RNA with [3H]uridine, and translation by labeling whole cell protein synthesis with [3H]leucine. Induction with dimethyl sulfoxide led to increased transcription of alpha, beta ma, and beta mi genes, and the proportion of beta mi RNA synthesized was similar to the proportion of beta mi globin protein produced, whether the cells produced 30-40% beta mi (lines 745 and 9M) or greater than 80% beta mi (clone 25-66). Induction with hemin did not lead to increased globin gene transcription in any line, although globin protein synthesis did increase. Thus, the mechanism of beta globin chain induction depends on the inducing agent, and not on the cell line or the type of beta globin gene product. The relative proportion of beta mi and beta ma globin chain proteins reflects the relative transcription of the two beta genes, whether or not transcription increased following induction.
Ganguly
S
S
Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461.
Skoultchi
A I
AI
Garrick
M D
MD
Garrick
L M
LM
Campbell
A S
AS
Alter
B P
BP
D000818:Animals; D004247:DNA / Q000378:metabolism; D004274:DNA, Recombinant / Q000378:metabolism; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005622:Friend murine leukemia virus; D005914:Globins / Q000096:biosynthesis* / Q000235:genetics; D006427:Hemin / Q000494:pharmacology; D007930:Leucine / Q000378:metabolism; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism*; D051379:Mice; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured; D014529:Uridine / Q000378:metabolism
D004274:DNA, Recombinant; D006427:Hemin; D005914:Globins; D004247:DNA; D007930:Leucine; D014529:Uridine; D004121:Dimethyl Sulfoxide