Department of Pediatrics
Cell Differentiation; Cytochrome b Group; *Gene Expression Regulation; Granulocytes; Humans; Leukemia, Myeloid; Phagocytes; RNA, Messenger; Tretinoin; Tumor Cells, Cultured
Life Sciences | Medicine and Health Sciences
The expression of the X-CGD gene, which encodes the heavy-chain subunit of the phagocyte cytochrome b, was studied during induced myeloid differentiation of HL-60 cells. Incubation of the cells with a combined regimen of retinoic acid and dimethyl formamide resulted in granulocytic morphological differentiation and acquisition of nitroblue tetrazolium reduction, a measure of superoxide generation. During the 5-day course of induced differentiation, the levels of X-CGD mRNA transcripts rose 13-fold, with a 2-fold increase detectable within 3 h of exposure to retinoic acid. Relative transcription rates for the X-CGD gene, determined by nuclear runoff, increased two- to eightfold after 24 to 72 h of induced differentiation. However, the greater change in X-CGD mRNA levels than that in transcription rates implies the involvement of posttranscriptional regulation as well. Fractionation by centrifugal elutriation into phases of the cell cycle showed expression of X-CGD transcripts predominantly in G1 cells before induction and in all phases of the cell cycle 24 h after induction. Thus the rapid increase in X-CGD expression in induced cells reflects the acquisition of functional competence and not the concomitant cessation of proliferation or shift in cell cycle distribution.
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Citation: Mol Cell Biol. 1988 Jul;8(7):2804-10.
Molecular and cellular biology
Barker, Kathleen A.; Orkin, Stuart H.; and Newburger, Peter E., "Expression of the X-CGD gene during induced differentiation of myeloid leukemia cell line HL-60" (1988). Open Access Articles. 1468.