Expression and posttranslational modification of class III beta-tubulin during neuronal differentiation of P19 embryonal carcinoma cells.
We have used a combination of immunofluorescence microscopy, northern blotting, ELISA, and isoelectric focusing to characterize the expression of neuronal Class III beta-tubulin in P19 embryonal carcinoma cells induced to differentiate along a neuronal pathway by retinoic acid. Following 48 h differentiation, beta-III tubulin mRNA is evident and beta-III tubulin appears in the mitotic spindle of neuroblasts. Neurite outgrowth is obvious by day 3, and beta-III tubulin protein and mRNA levels increase concurrently until approximately day 7, when beta-III mRNA levels begin to decrease while protein levels remain high. In addition, increasingly acidic beta-III tubulin isoforms appear during neuronal differentiation. The expression of these isoelectric variants occurs concomitant with a temporal increase in the levels of beta-III tubulin present in the colchicine-stable microtubules. These results implicate posttranslational modifications of beta-III tubulin in the increased microtubule stability noted in differentiating P19 neurons.
Department of Biology, University of Ottawa, Ontario, Canada.
N B
NB
Laferrière
D L
DL
Brown
D000818:Animals; D002454:Cell Differentiation; D003078:Colchicine / Q000494:pharmacology; D015870:Gene Expression; D051379:Mice; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D011499:Protein Processing, Post-Translational; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D014404:Tubulin; D003078:Colchicine