scholarly journals Gene-specific signal transduction between microtubules and tubulin genes in Tetrahymena thermophila.

1995 ◽  
Vol 15 (9) ◽  
pp. 5173-5179 ◽  
Author(s):  
L Gu ◽  
J Gaertig ◽  
L A Stargell ◽  
M A Gorovsky
Keyword(s):  
Gene Expression ◽  
Signal Transduction ◽  
Mammalian Cells ◽  
Tetrahymena Thermophila ◽  
Tubulin Gene ◽  
Beta Tubulin ◽  
Alpha Tubulin ◽  
Tubulin Genes ◽  
Cell Biol ◽  
Tubulin Mrna

Mammalian cells regulate tubulin mRNA abundance by a posttranscriptional mechanism dependent on the concentration of tubulin monomer. Treatment of mammalian cells with microtubule-depolymerizing drugs and microtubule-polymerizing drugs causes decreases and increases in tubulin mRNA, respectively (D. W. Cleveland, Curr. Opin. Cell Biol. 1:10-14, 1989). In striking contrast to the case with mammalian cells, perturbation of microtubules in Tetrahymena thermophila by microtubule-depolymerizing or -polymerizing drugs increases the level of the single alpha-tubulin gene message by increasing transcription (L. A. Stargell, D. P. Heruth, J. Gaertig, and M. A. Gorovsky, Mol. Cell. Biol. 12:1443-1450, 1992). In this report we show that antimicrotubule drugs preferentially induce the expression of one of two beta-tubulin genes (BTU1) in T. thermophila. In contrast, deciliation induces expression of both beta-tubulin genes. Tubulin gene expression was examined in a mutant strain created by transformation with an in vitro-mutagenized beta-tubulin gene that conferred resistance to microtubule-depolymerizing drugs and sensitivity to the polymerizing drug taxol and in a strain containing a nitrosoguanidine-induced mutation in the single alpha-tubulin gene that conferred the same pattern of drug sensitivities. In both cases the levels of tubulin mRNA expression from the drug-inducible BTU1 gene in the mutant cells paralleled the altered growth sensitivities to microtubule drugs. These studies demonstrate that T. thermophila has distinct, gene-specific mechanisms for modulating tubulin gene expression depending on whether ciliary or cytoplasmic microtubules are involved. They also show that the cytoplasmic microtubule cytoskeleton itself participates in a signal transduction pathway that regulates specific tubulin gene transcription in T. thermophila.

Transcriptional regulation of tubulin gene expression in differentiating trochoblasts during early development of Patella vulgata

Development ◽  
1994 ◽  
Vol 120 (10) ◽  
pp. 2835-2845
Author(s):  
W.G. Damen ◽  
L.A. van Grunsven ◽  
A.E. van Loon
Keyword(s):  
Gene Expression ◽  
Gene Product ◽  
Cell Lines ◽  
Upstream Region ◽  
Tubulin Gene ◽  
Beta Tubulin ◽  
Cell Stage ◽  
Alpha Tubulin ◽  
Tubulin Genes ◽  
Tubulin Mrna

The expression of alpha- and beta-tubulin genes during the early development of the marine mollusk Patella vulgata has been investigated. From the 32-cell stage onwards, an enhanced expression of both alpha- and beta-tubulin mRNAs was detected in the primary trochoblasts. After one additional cleavage, these cells become cleavage-arrested and then form cilia. They are the first cells to differentiate during Patella development. Later, alpha- and beta-tubulin mRNA is also found in the accessory and secondary trochoblasts. Together these three cell-lines form the prototroch, the ciliated locomotory organ of the trochophore larva. The early and abundant expression of tubulin genes precede and accompany cilia formation in the trochoblasts and provides us with an excellent molecular differentiation marker for these cells. Apart from the trochoblasts, tubulin gene expression was also found in other cells at some stages. At the 88-cell stage, elevated tubulin mRNA levels were found around the large nucleus of the mesodermal stem cell 4d. In later stages, tubulin gene expression was detected in the cells that form the flagella of the apical tuft and in the refractive bodies. An alpha-tubulin gene was isolated and characterized. A lacZ fusion gene under control of the 5′ upstream region of this tubulin gene was microinjected into embryos at the two-cell stage. The reporter gene product was only detected in the three trochoblast cell-lines at the same time as tubulin genes were expressed in these cells. Reporter gene product was not detected in any other cells. Thus, this 5′ upstream region of this alpha-tubulin gene contains all the elements required for the correct spatiotemporal pattern of expression.

Drugs affecting microtubule dynamics increase alpha-tubulin mRNA accumulation via transcription in Tetrahymena thermophila

1992 ◽  
Vol 12 (4) ◽  
pp. 1443-1450
Author(s):  
L A Stargell ◽  
D P Heruth ◽  
J Gaertig ◽  
M A Gorovsky
Keyword(s):  
Mammalian Cells ◽  
Transcriptional Activity ◽  
Actinomycin D ◽  
Tetrahymena Thermophila ◽  
Rapid Decline ◽  
Mrna Accumulation ◽  
Alpha Tubulin ◽  
Tubulin Genes ◽  
Tubulin Mrna ◽  
The Stability

In cultured mammalian cells, an increase in the amount of tubulin monomer due to treatment with a microtubule-depolymerizing agent results in a rapid decline in tubulin synthesis. This autoregulatory response is mediated through a posttranscriptional mechanism which decreases the stability of tubulin message with no change in transcriptional activity of tubulin genes. Conversely, treatment with a microtubule-polymerizing drug, such as taxol, results in a slight increase in the synthesis of tubulin. Surprisingly, we find that two microtubule-depolymerizing agents, colchicine and oryzalin, actually cause an increase in alpha-tubulin synthesis and alpha-tubulin message in starved Tetrahymena thermophila. This increase is paralleled by an increase in transcription of alpha-tubulin sequences measured by run-on transcription, while the half-life of tubulin message measured by decay in the presence of actinomycin D does not change appreciably. Treatment of starved cells with taxol also produces an increase in alpha-tubulin synthesis via an increase in message abundance due to an increase in transcription of the alpha-tubulin gene. These results indicate that tubulin synthesis in T. thermophila is regulated very differently than in cultured mammalian cells.

scholarly journals Drugs affecting microtubule dynamics increase alpha-tubulin mRNA accumulation via transcription in Tetrahymena thermophila.

1992 ◽  
Vol 12 (4) ◽  
pp. 1443-1450 ◽  
Author(s):  
L A Stargell ◽  
D P Heruth ◽  
J Gaertig ◽  
M A Gorovsky
Keyword(s):  
Mammalian Cells ◽  
Transcriptional Activity ◽  
Actinomycin D ◽  
Tetrahymena Thermophila ◽  
Rapid Decline ◽  
Mrna Accumulation ◽  
Alpha Tubulin ◽  
Tubulin Genes ◽  
Tubulin Mrna ◽  
The Stability

In cultured mammalian cells, an increase in the amount of tubulin monomer due to treatment with a microtubule-depolymerizing agent results in a rapid decline in tubulin synthesis. This autoregulatory response is mediated through a posttranscriptional mechanism which decreases the stability of tubulin message with no change in transcriptional activity of tubulin genes. Conversely, treatment with a microtubule-polymerizing drug, such as taxol, results in a slight increase in the synthesis of tubulin. Surprisingly, we find that two microtubule-depolymerizing agents, colchicine and oryzalin, actually cause an increase in alpha-tubulin synthesis and alpha-tubulin message in starved Tetrahymena thermophila. This increase is paralleled by an increase in transcription of alpha-tubulin sequences measured by run-on transcription, while the half-life of tubulin message measured by decay in the presence of actinomycin D does not change appreciably. Treatment of starved cells with taxol also produces an increase in alpha-tubulin synthesis via an increase in message abundance due to an increase in transcription of the alpha-tubulin gene. These results indicate that tubulin synthesis in T. thermophila is regulated very differently than in cultured mammalian cells.

Phenotypic consequences of tubulin overproduction in Saccharomyces cerevisiae: differences between alpha-tubulin and beta-tubulin

1990 ◽  
Vol 10 (10) ◽  
pp. 5295-5304
Author(s):  
B Weinstein ◽  
F Solomon
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Division ◽  
Microtubule Assembly ◽  
Beta Tubulin ◽  
Alpha Tubulin ◽  
Tubulin Genes ◽  
Data Support ◽  
Cell Biol

Overexpression of alpha- and beta-tubulin genes in Saccharomyces cerevisiae, separately or together, leads to accumulation of large excesses of each of the polypeptides and arrest of cell division. However, other consequences of overexpression of these genes differ in several ways. As shown previously (D. Burke, P. Gasdaska, and L. Hartwell, Mol. Cell. Biol. 9:1049-1059, 1989), overexpression of beta-tubulin leads, at early times, to loss of microtubule structures and loss of viability. Eventually, the excess beta-tubulin forms abnormal structures. We show here that, in contrast, overexpression of alpha-tubulin led to none of these phenotypes and in fact could suppress each of the phenotypes associated with beta-tubulin accumulation. Truncated forms of beta-tubulin that were not competent to carry out microtubule functions also failed to elicit the beta-tubulin-specific phenotypes when overexpressed. The data support the hypothesis that beta-tubulin in excess over alpha-tubulin is uniquely toxic, perhaps because it interferes with normal microtubule assembly.

scholarly journals The alpha-tubulin gene family expressed during cell differentiation in Naegleria gruberi.

1988 ◽  
Vol 106 (6) ◽  
pp. 2035-2046 ◽  
Author(s):  
E Y Lai ◽  
S P Remillard ◽  
C Fulton
Keyword(s):  
Gene Family ◽  
Gene Organization ◽  
Cdna Clones ◽  
Tubulin Gene ◽  
Alpha Tubulin ◽  
Tubulin Genes ◽  
Tubulin Mrna ◽  
Protein Conservation ◽  
Naegleria Gruberi

Genes that direct the programmed synthesis of flagellar alpha-tubulin during the differentiation of Naegleria gruberi from amebae to flagellates have been cloned, and found to be novel with respect to gene organization, sequence, and conservation. The flagellar alpha-tubulin gene family is represented in the genome by about eight homologous DNA segments that are exceptionally similar and yet are neither identical nor arrayed in a short tandem repeat. The coding regions of three of these genes have been sequenced, two from cDNA clones and one from an intronless genomic gene. These three genes encode an identical alpha-tubulin that is conserved relative to the alpha-tubulins of other organisms except at the carboxyl terminus, where the protein is elongated by two residues and ends in a terminal glutamine instead of the canonical tyrosine. In spite of the protein conservation, the Naegleria DNA sequence has diverged markedly from the alpha-tubulin genes of other organisms, a counterexample to the idea that tubulin genes are conserved. alpha-Tubulin mRNA homologous to this gene family has not been detected in amebae. This mRNA increases markedly in abundance during the first hour of differentiation, and then decreases even more rapidly with a half-life of approximately 8 min. The abundance of physical alpha-tubulin mRNA rises and subsequently falls in parallel with the abundance of translatable flagellar tubulin mRNA and with the in vivo rate of flagellar tubulin synthesis, which indicates that flagellar tubulin synthesis is directly regulated by the relative rates of transcription and mRNA degradation.

scholarly journals Phenotypic consequences of tubulin overproduction in Saccharomyces cerevisiae: differences between alpha-tubulin and beta-tubulin.

1990 ◽  
Vol 10 (10) ◽  
pp. 5295-5304 ◽  
Author(s):  
B Weinstein ◽  
F Solomon
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Division ◽  
Microtubule Assembly ◽  
Beta Tubulin ◽  
Alpha Tubulin ◽  
Tubulin Genes ◽  
Data Support ◽  
Cell Biol

Overexpression of alpha- and beta-tubulin genes in Saccharomyces cerevisiae, separately or together, leads to accumulation of large excesses of each of the polypeptides and arrest of cell division. However, other consequences of overexpression of these genes differ in several ways. As shown previously (D. Burke, P. Gasdaska, and L. Hartwell, Mol. Cell. Biol. 9:1049-1059, 1989), overexpression of beta-tubulin leads, at early times, to loss of microtubule structures and loss of viability. Eventually, the excess beta-tubulin forms abnormal structures. We show here that, in contrast, overexpression of alpha-tubulin led to none of these phenotypes and in fact could suppress each of the phenotypes associated with beta-tubulin accumulation. Truncated forms of beta-tubulin that were not competent to carry out microtubule functions also failed to elicit the beta-tubulin-specific phenotypes when overexpressed. The data support the hypothesis that beta-tubulin in excess over alpha-tubulin is uniquely toxic, perhaps because it interferes with normal microtubule assembly.

Structure and arrangement of the beta-tubulin genes of Leishmania tropica

1984 ◽  
Vol 4 (7) ◽  
pp. 1372-1383
Author(s):  
P L Huang ◽  
B E Roberts ◽  
D M Pratt ◽  
J R David ◽  
J S Miller
Keyword(s):  
Protozoan Parasite ◽  
Leishmania Tropica ◽  
Beta Tubulin ◽  
S1 Nuclease ◽  
Alpha Tubulin ◽  
Tubulin Genes ◽  
Repeat Units ◽  
Genes Encoding ◽  
Tubulin Mrna ◽  
Parasite Leishmania

We studied the organization and arrangement of the genes encoding beta-tubulin in the protozoan parasite Leishmania tropica and examined the structure and orientation of the beta-tubulin mRNA relative to the gene. There were found to be eight to nine beta-tubulin genes arranged in an array of direct tandem repeat units with a length of 3.8 kilobase pairs, and they were extremely homologous, if not identical, in sequence. These repeat units did not contain the alpha-tubulin genes. The transcribed sequences within the beta-tubulin genes were localized, and the orientation of the major alpha-tubulin mRNA was mapped on the gene by S1 nuclease analysis.

scholarly journals Structure and arrangement of the beta-tubulin genes of Leishmania tropica.

1984 ◽  
Vol 4 (7) ◽  
pp. 1372-1383 ◽  
Author(s):  
P L Huang ◽  
B E Roberts ◽  
D M Pratt ◽  
J R David ◽  
J S Miller
Keyword(s):  
Protozoan Parasite ◽  
Leishmania Tropica ◽  
Beta Tubulin ◽  
S1 Nuclease ◽  
Alpha Tubulin ◽  
Tubulin Genes ◽  
Repeat Units ◽  
Genes Encoding ◽  
Tubulin Mrna ◽  
Parasite Leishmania

We studied the organization and arrangement of the genes encoding beta-tubulin in the protozoan parasite Leishmania tropica and examined the structure and orientation of the beta-tubulin mRNA relative to the gene. There were found to be eight to nine beta-tubulin genes arranged in an array of direct tandem repeat units with a length of 3.8 kilobase pairs, and they were extremely homologous, if not identical, in sequence. These repeat units did not contain the alpha-tubulin genes. The transcribed sequences within the beta-tubulin genes were localized, and the orientation of the major alpha-tubulin mRNA was mapped on the gene by S1 nuclease analysis.

scholarly journals alpha-Tubulin limits its own synthesis: evidence for a mechanism involving translational repression.

1996 ◽  
Vol 135 (6) ◽  
pp. 1525-1534 ◽  
Author(s):  
M L Gonzalez-Garay ◽  
F Cabral
Keyword(s):  
Mammalian Cells ◽  
Chinese Hamster ◽  
Mrna Levels ◽  
Beta Tubulin ◽  
Alpha Tubulin ◽  
Transfected Cells ◽  
Influenza Hemagglutinin ◽  
Tubulin Mrna ◽  
Ribonuclease Protection ◽  
Expression In Mammalian Cells

A Chinese hamster alpha-tubulin cDNA was modified to encode an 11-amino acid carboxyl-terminal extension containing the immunodominant epitope from influenza hemagglutinin antigen (to create HA alpha 1-tubulin) and was cloned into a vector for expression in mammalian cells. 12 stable CHO cell lines expressing this HA alpha 1-tubulin were isolated and characterized. HA alpha 1-tubulin incorporated into all classes of microtubules, assembled to the same extent as the endogenous tubulin, and did not perturb the growth of the cells in which it was expressed. However, overexpression of HA alpha 1-tubulin strongly repressed the synthesis of endogenous alpha-tubulin while having little or no effect on the synthesis of beta-tubulin. Treatment of transfected cells with sodium butyrate to induce even greater expression of HA alpha 1-tubulin led to a further decrease in synthesis of endogenous alpha-tubulin that was fully reversible upon removal of the inducer. Decreased synthesis of alpha-tubulin in transfected cells did not result from decreased levels of alpha-tubulin mRNA, as demonstrated by ribonuclease protection assays. On the other hand, colchicine, a drug previously shown to destabilize the tubulin message, caused a clear reduction in both protein synthesis and mRNA levels for transfected HA alpha 1-tubulin and endogenous alpha-tubulin, thus indicating that the decreased alpha-tubulin synthesis observed as a result of HA alpha 1-tubulin overexpression is distinct from the previously described autoregulation of tubulin. The results are consistent with a mechanism in which free alpha-tubulin inhibits the translation of its own message as a way of ensuring stoichiometric synthesis of alpha- and beta-tubulin.

Tandem arrangement of tubulin genes in the protozoan parasite Leishmania enriettii

1983 ◽  
Vol 3 (6) ◽  
pp. 1070-1076
Author(s):  
S M Landfear ◽  
D McMahon-Pratt ◽  
D F Wirth
Keyword(s):  
Tandem Repeat ◽  
Blot Hybridization ◽  
Protozoan Parasite ◽  
Southern Blot Hybridization ◽  
Beta Tubulin ◽  
Developmentally Regulated ◽  
Alpha Tubulin ◽  
Tubulin Genes ◽  
Southern Blot Hybridization Analysis ◽  
Leishmania Enriettii

The arrangement of developmentally regulated alpha- and beta-tubulin genes has been studied in the parasitic protozoan Leishmania enriettii by using Southern blot hybridization analysis. The alpha-tubulin genes occur in a tandem repeat whose monomeric unit may be represented by a 2-kilobase PstI fragment. Similarly, the beta-tubulin genes probably occur in a separate tandem repeat consisting of approximately 4-kilobase units unlinked to the alpha-tubulin repeats.

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