Human globin gene expression in hybrid 2S MEL X human fibroblast cells.
A somatic cell hybrid line, called M11-X, was developed in order to study the expression and regulation of the human beta-like globin genes in a mouse erythroid environment. M11-X cells were obtained by fusing the human fibroblast cell line GM3552 (which contains the translocation chromosome t(11;X) that carries the human beta-like globin genes) with hypoxanthine phosphoribosyltransferase (HPRT) -negative tetraploid (2S) mouse erythroleukemia (MEL) cells. After induction with 5 mM hexamethylene bisacetamide (HMBA), these cells contain approximately 300-600 copies per cell of correctly initiated, processed, and terminated human beta-globin mRNA; however, neither human epsilon- nor gamma-globin mRNAs were detected. Carboxymethylcellulose chromatography followed by SDS-polyacrylamide gel electrophoresis and Western blotting revealed that normal human beta-globin protein was also present. These results suggest that the human beta-globin gene, when present in mouse erythroid cells, can be transcribed and its mRNA translated into normal products, but at a much lower level than the mouse beta-globin genes. Analysis of the frequency of cytosine methylation near the human gamma-globin genes indicated that these genes are heavily methylated in M11-X cells. The inability to express the human gamma-globin genes of these cells might be accounted for, at least in part, by DNA methylation.
D000818:Animals; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D005914:Globins / Q000235:genetics*; D006801:Humans; D006822:Hybrid Cells / Q000502:physiology; D004915:Leukemia, Erythroblastic, Acute / Q000235:genetics; D008745:Methylation; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
D012333:RNA, Messenger; D005914:Globins