Abstract
The steady-state level of alpha- and beta-tubulin synthesis is autoregulated by a posttranscriptional mechanism that selectively alters alpha- and beta-tubulin mRNA levels in response to changes in the unassembled tubulin subunit concentration. For beta-tubulin mRNAs, previous efforts have shown that this is the result of a selective mRNA degradation mechanism which involves cotranslational recognition of the nascent amino-terminal beta-tubulin tetrapeptide as it emerges from the ribosome. Site-directed mutagenesis is now used to determine that the minimal sequence requirement for conferring the full range of beta-tubulin autoregulation is the amino-terminal tetrapeptide MR(E/D)I. Although tubulin-dependent changes in alpha-tubulin mRNA levels are shown to result from changes in cytoplasmic mRNA stability, transfection of wild-type and mutated alpha-tubulin genes reveals that alpha- and beta-tubulin mRNA degradation is not mediated through a common pathway. Not only does the amino-terminal alpha-tubulin tetrapeptide MREC fail to confer regulated mRNA degradation, neither wild-type alpha-tubulin transgenes nor an alpha-tubulin gene mutated to encode an amino-terminal MREI yields mRNAs that are autoregulated. Further, although slowing ribosome transit accelerates the autoregulated degradation of endogenous alpha- and beta-tubulin mRNAs, degradation of alpha-tubulin transgene mRNAs is not enhanced, and in one case, the mRNA is actually stabilized. We conclude that, despite similarities, alpha- and beta-tubulin mRNA destabilization pathways utilize divergent determinants to link RNA instability to tubulin subunit concentrations.
Full text
PDF![4076](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/193cbee7ed73/molcellb00006-0558.png)
![4077](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/73d3577f4ac1/molcellb00006-0559.png)
![4078](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/74fa2beefcd0/molcellb00006-0560.png)
![4079](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/88f3c54b9166/molcellb00006-0561.png)
![4080](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/c2ccab53ee29/molcellb00006-0562.png)
![4081](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/74714d366e26/molcellb00006-0563.png)
![4082](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/b7ca79c714e5/molcellb00006-0564.png)
![4083](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/afa879333d43/molcellb00006-0565.png)
![4084](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/5f81df0fd826/molcellb00006-0566.png)
![4085](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/52e59d505e0b/molcellb00006-0567.png)
![4086](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/2828/358773/34ee376dd696/molcellb00006-0568.png)
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Ben-Ze'ev A., Farmer S. R., Penman S. Mechanisms of regulating tubulin synthesis in cultured mammalian cells. Cell. 1979 Jun;17(2):319–325. doi: 10.1016/0092-8674(79)90157-0. [DOI] [PubMed] [Google Scholar]
- Caron J. M., Jones A. L., Rall L. B., Kirschner M. W. Autoregulation of tubulin synthesis in enucleated cells. Nature. 1985 Oct 17;317(6038):648–651. doi: 10.1038/317648a0. [DOI] [PubMed] [Google Scholar]
- Cleveland D. W. Autoregulated control of tubulin synthesis in animal cells. Curr Opin Cell Biol. 1989 Feb;1(1):10–14. doi: 10.1016/s0955-0674(89)80030-4. [DOI] [PubMed] [Google Scholar]
- Cleveland D. W., Havercroft J. C. Is apparent autoregulatory control of tubulin synthesis nontranscriptionally regulated? J Cell Biol. 1983 Sep;97(3):919–924. doi: 10.1083/jcb.97.3.919. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cleveland D. W., Lopata M. A., Sherline P., Kirschner M. W. Unpolymerized tubulin modulates the level of tubulin mRNAs. Cell. 1981 Aug;25(2):537–546. doi: 10.1016/0092-8674(81)90072-6. [DOI] [PubMed] [Google Scholar]
- Cleveland D. W., Pittenger M. F., Feramisco J. R. Elevation of tubulin levels by microinjection suppresses new tubulin synthesis. Nature. 1983 Oct 20;305(5936):738–740. doi: 10.1038/305738a0. [DOI] [PubMed] [Google Scholar]
- Coulson R. M., Cleveland D. W. Ferritin synthesis is controlled by iron-dependent translational derepression and by changes in synthesis/transport of nuclear ferritin RNAs. Proc Natl Acad Sci U S A. 1993 Aug 15;90(16):7613–7617. doi: 10.1073/pnas.90.16.7613. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cowan N. J., Dobner P. R., Fuchs E. V., Cleveland D. W. Expression of human alpha-tubulin genes: interspecies conservation of 3' untranslated regions. Mol Cell Biol. 1983 Oct;3(10):1738–1745. doi: 10.1128/mcb.3.10.1738. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Decker C. J., Parker R. A turnover pathway for both stable and unstable mRNAs in yeast: evidence for a requirement for deadenylation. Genes Dev. 1993 Aug;7(8):1632–1643. doi: 10.1101/gad.7.8.1632. [DOI] [PubMed] [Google Scholar]
- Elliott E. M., Henderson G., Sarangi F., Ling V. Complete sequence of three alpha-tubulin cDNAs in Chinese hamster ovary cells: each encodes a distinct alpha-tubulin isoprotein. Mol Cell Biol. 1986 Mar;6(3):906–913. doi: 10.1128/mcb.6.3.906. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Favaloro J., Treisman R., Kamen R. Transcription maps of polyoma virus-specific RNA: analysis by two-dimensional nuclease S1 gel mapping. Methods Enzymol. 1980;65(1):718–749. doi: 10.1016/s0076-6879(80)65070-8. [DOI] [PubMed] [Google Scholar]
- Gay D. A., Sisodia S. S., Cleveland D. W. Autoregulatory control of beta-tubulin mRNA stability is linked to translation elongation. Proc Natl Acad Sci U S A. 1989 Aug;86(15):5763–5767. doi: 10.1073/pnas.86.15.5763. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gay D. A., Yen T. J., Lau J. T., Cleveland D. W. Sequences that confer beta-tubulin autoregulation through modulated mRNA stability reside within exon 1 of a beta-tubulin mRNA. Cell. 1987 Aug 28;50(5):671–679. doi: 10.1016/0092-8674(87)90325-4. [DOI] [PubMed] [Google Scholar]
- Gong Z. Y., Brandhorst B. P. Stabilization of tubulin mRNA by inhibition of protein synthesis in sea urchin embryos. Mol Cell Biol. 1988 Aug;8(8):3518–3525. doi: 10.1128/mcb.8.8.3518. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Graham F. L., van der Eb A. J. A new technique for the assay of infectivity of human adenovirus 5 DNA. Virology. 1973 Apr;52(2):456–467. doi: 10.1016/0042-6822(73)90341-3. [DOI] [PubMed] [Google Scholar]
- Graves R. A., Pandey N. B., Chodchoy N., Marzluff W. F. Translation is required for regulation of histone mRNA degradation. Cell. 1987 Feb 27;48(4):615–626. doi: 10.1016/0092-8674(87)90240-6. [DOI] [PubMed] [Google Scholar]
- Kislauskis E. H., Singer R. H. Determinants of mRNA localization. Curr Opin Cell Biol. 1992 Dec;4(6):975–978. doi: 10.1016/0955-0674(92)90128-y. [DOI] [PubMed] [Google Scholar]
- Lawrence J. B., Singer R. H., Marselle L. M. Highly localized tracks of specific transcripts within interphase nuclei visualized by in situ hybridization. Cell. 1989 May 5;57(3):493–502. doi: 10.1016/0092-8674(89)90924-0. [DOI] [PubMed] [Google Scholar]
- Lee M. G., Lewis S. A., Wilde C. D., Cowan N. J. Evolutionary history of a multigene family: an expressed human beta-tubulin gene and three processed pseudogenes. Cell. 1983 Jun;33(2):477–487. doi: 10.1016/0092-8674(83)90429-4. [DOI] [PubMed] [Google Scholar]
- Lemischka I. R., Farmer S., Racaniello V. R., Sharp P. A. Nucleotide sequence and evolution of a mammalian alpha-tubulin messenger RNA. J Mol Biol. 1981 Sep 5;151(1):101–120. doi: 10.1016/0022-2836(81)90223-0. [DOI] [PubMed] [Google Scholar]
- Lemischka I., Sharp P. A. The sequences of an expressed rat alpha-tubulin gene and a pseudogene with an inserted repetitive element. Nature. 1982 Nov 25;300(5890):330–335. doi: 10.1038/300330a0. [DOI] [PubMed] [Google Scholar]
- Lopata M. A., Cleveland D. W., Sollner-Webb B. High level transient expression of a chloramphenicol acetyl transferase gene by DEAE-dextran mediated DNA transfection coupled with a dimethyl sulfoxide or glycerol shock treatment. Nucleic Acids Res. 1984 Jul 25;12(14):5707–5717. doi: 10.1093/nar/12.14.5707. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Maquat L. E. Nuclear mRNA export. Curr Opin Cell Biol. 1991 Dec;3(6):1004–1012. doi: 10.1016/0955-0674(91)90121-e. [DOI] [PubMed] [Google Scholar]
- Pachter J. S., Yen T. J., Cleveland D. W. Autoregulation of tubulin expression is achieved through specific degradation of polysomal tubulin mRNAs. Cell. 1987 Oct 23;51(2):283–292. doi: 10.1016/0092-8674(87)90155-3. [DOI] [PubMed] [Google Scholar]
- Pittenger M. F., Cleveland D. W. Retention of autoregulatory control of tubulin synthesis in cytoplasts: demonstration of a cytoplasmic mechanism that regulates the level of tubulin expression. J Cell Biol. 1985 Nov;101(5 Pt 1):1941–1952. doi: 10.1083/jcb.101.5.1941. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Savant-Bhonsale S., Cleveland D. W. Evidence for instability of mRNAs containing AUUUA motifs mediated through translation-dependent assembly of a > 20S degradation complex. Genes Dev. 1992 Oct;6(10):1927–1939. doi: 10.1101/gad.6.10.1927. [DOI] [PubMed] [Google Scholar]
- Sawada T., Cabral F. Expression and function of beta-tubulin isotypes in Chinese hamster ovary cells. J Biol Chem. 1989 Feb 15;264(5):3013–3020. [PubMed] [Google Scholar]
- Sisodia S. S., Gay D. A., Cleveland D. W. In vivo discrimination among beta-tubulin isotypes: selective degradation of a type IV beta-tubulin isotype following overexpression in cultured animal cells. New Biol. 1990 Jan;2(1):66–76. [PubMed] [Google Scholar]
- Southern P. J., Berg P. Transformation of mammalian cells to antibiotic resistance with a bacterial gene under control of the SV40 early region promoter. J Mol Appl Genet. 1982;1(4):327–341. [PubMed] [Google Scholar]
- Sullivan K. F., Cleveland D. W. Identification of conserved isotype-defining variable region sequences for four vertebrate beta tubulin polypeptide classes. Proc Natl Acad Sci U S A. 1986 Jun;83(12):4327–4331. doi: 10.1073/pnas.83.12.4327. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sullivan K. F. Structure and utilization of tubulin isotypes. Annu Rev Cell Biol. 1988;4:687–716. doi: 10.1146/annurev.cb.04.110188.003351. [DOI] [PubMed] [Google Scholar]
- Theodorakis N. G., Cleveland D. W. Physical evidence for cotranslational regulation of beta-tubulin mRNA degradation. Mol Cell Biol. 1992 Feb;12(2):791–799. doi: 10.1128/mcb.12.2.791. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wong P. C., Cleveland D. W. Characterization of dominant and recessive assembly-defective mutations in mouse neurofilament NF-M. J Cell Biol. 1990 Nov;111(5 Pt 1):1987–2003. doi: 10.1083/jcb.111.5.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yen T. J., Gay D. A., Pachter J. S., Cleveland D. W. Autoregulated changes in stability of polyribosome-bound beta-tubulin mRNAs are specified by the first 13 translated nucleotides. Mol Cell Biol. 1988 Mar;8(3):1224–1235. doi: 10.1128/mcb.8.3.1224. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yen T. J., Machlin P. S., Cleveland D. W. Autoregulated instability of beta-tubulin mRNAs by recognition of the nascent amino terminus of beta-tubulin. Nature. 1988 Aug 18;334(6183):580–585. doi: 10.1038/334580a0. [DOI] [PubMed] [Google Scholar]