Tissue-specific Expression of Distinct Spectrin and Ankyrin Transcripts in Erythroid and Nonerythroid Cells
cDNA probes for three components of the erythroid membrane skeleton, α spectrin, β spectrin, and ankyrin, were obtained by using monospecific antibodies to screen a λgt11 expression vector library containing cDNA prepared from chicken erythroid poly(A)^+ RNA. Each cDNA appears to hybridize to one gene type in the chicken genome. Qualitatively distinct RNA species in myogenic and erythroid cells are detected for β spectrin and ankyrin, while α spectrin exists as a single species of transcript in all tissues examined. This tissue-specific expression of RNAs is regulated quantitatively during myogenesis in vitro, since all three accumulate only upon myoblast fusion. Furthermore, RNAs for two of the three genes do not accumulate to detectable levels in chicken embryo fibroblasts, demonstrating that their accumulation can be noncoordinate. These observations suggest that independent gene regulation and tissue-specific production of heterogeneous transcripts from the β spectrin and ankyrin genes underlie the formation of distinct membrane skeletons in erythroid and muscle cells.
Additional Information© 1985 The Rockefeller University Press. Received for publication 4 October 1984, and in revised form 15 October 1984. We thank Professor Norman Davidson and Dr. Yassemi Capetanaki for helpful conversations, and Dr. W. J. Nelson for assistance in cell culture. This work was supported by grants from the National Institutes of Health, the National Science Foundation, and the Muscular Dystrophy Association of America. R. T. Moon was supported by a postdoctoral fellowship from the American Cancer Society, J. Ngai by a Gordon Ross Foundation Predoctoral Fellowship, B. J. Wold by the National Institutes of Health, the Searle Foundation, and a Rita Allen Fellowship, and E. Lazarides by a Research Career Development Award. Note Added in Proof. The observation that erythroid cells contain an 8.8 kb transcript and myotubes contain a 3.4 kb transcript, both of which hybridize to the pA4-1 ankyrin cDNA (see Fig. 7), has been substantiated with another ankyrin cDNA.
Published - MOOjcb85.pdf