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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The relationship between the primary sequence of tubulins and their properties in cells was studied by gene transfection experiments. Previously, we studied a chimeric beta-tubulin formed from chicken beta-tubulin-2 sequences in the amino-terminal portion and the highly divergent Saccharomyces cerevisiae TUB2 sequences in the carboxy-terminal 25% of the molecule. In the cytoplasm of cultured animal cells, this protein incorporates into all microtubule structures and assembles with the same efficiency as endogenous tubulin. We show that the protein products of chimeric genes with an increasing proportion of yeast sequence, extending 5' of the carboxy-terminal 25%, are abnormal in two ways. First, they assemble with a significantly lower efficiency than the original chimeric protein or the endogenous tubulins. Second, they are less stable in the cytoplasm. The results suggest that the position of the yeast sequences is crucial in determining the properties of the molecule. Results of analyses of 1 deletion mutation and 10 linker insertions in the original chimeric tubulin suggest that those changes made outside the carboxyl terminus completely disrupt assembly activity, while those made in the carboxyl terminus do not.
Mol Cell Biol 1987 Oct
PMID:Domains of beta-tubulin essential for conserved functions in vivo. 289 Oct 28

The tubulins of Brugia malayi and B. pahangi were similar with respect to concentration (mg tubulin per mg soluble protein), electrophoretic and isoelectric mobility, reaction in Western blots with anti-tubulin monoclonal antibodies, and isoform patterns. Tubulin was estimated to account for 2.8% and 2.9% of soluble protein in B. malayi and B. pahangi extracts, respectively. Tubulins from Brugia nematodes have been partially purified by polylysine agarose chromatography and with taxol. Western blots with alpha- and beta-tubulin monoclonal antibodies confirmed the presence of tubulin. The mobility of Brugia tubulins on sodium dodecyl sulfate polyacrylamide gel electrophoresis was very similar to that of N. brasiliensis and rat brain tubulins. The isoelectric range for Brugia alpha- and beta-tubulin isoforms was pH 5.4-4.7. Western blots with anti-tubulin monoclonal antibodies revealed 4-5 isoforms of alpha-tubulin and 4-5 isoforms of beta-tubulin for Brugia nematodes.
Mol Biochem Parasitol 1989 Jan 15
PMID:Characterization of tubulin from Brugia malayi and Brugia pahangi. 292 43

We cloned the beta-tubulin gene of Neurospora crassa from a benomyl-resistant strain and determined its nucleotide sequence. The gene encodes a 447-residue protein which shows strong homology to other beta-tubulins. The coding region is interrupted by six introns, five of which are within the region coding for the first 54 amino acids of the protein. Intron position comparisons between the N. crassa gene and other fungal beta-tubulin genes reveal considerable positional conservation. The mutation responsible for benomyl resistance was determined; it caused a phenylalanine-to-tyrosine change at position 167. Codon usage in the beta-tubulin gene is biased, as has been observed for other abundantly expressed N. crassa genes such as am and the H3 and H4 histone genes. This bias results in pyrimidines in the third positions of 96% of the codons in codon families in which there is a choice between purines and pyrimidines in this position. Bias is also evident by the absence of 19 of the 61 sense codons. We demonstrated that benomyl resistance is due to the cloned beta-tubulin gene of strain Bml511(r)a and that this gene can be used as a dominant selectable marker in N. crassa transformation.
Mol Cell Biol 1986 Jul
PMID:Cloning and characterization of the gene for beta-tubulin from a benomyl-resistant mutant of Neurospora crassa and its use as a dominant selectable marker. 294 38

Two alpha-tubulin genes from the budding yeast Saccharomyces cerevisiae were identified and cloned by cross-species DNA homology. Nucleotide sequencing studies revealed that the two genes, named TUB1 and TUB3, encoded gene products of 447 and 445 amino acids, respectively, that are highly homologous to alpha-tubulins from other species. Comparison of the sequences of the two genes revealed a 19% divergence between the nucleotide sequences and a 10% divergence between the amino acid sequences. Each gene had a single intervening sequence, located at an identical position in codon 9. Cell fractionation studies showed that both gene products were present in yeast microtubules. These two genes, along with the TUB2 beta-tubulin gene, probably encode the entire complement of tubulin in budding yeast cells.
Mol Cell Biol 1986 Nov
PMID:Two functional alpha-tubulin genes of the yeast Saccharomyces cerevisiae encode divergent proteins. 302 10

We have determined the nucleotide sequence of the chicken beta 5 (c beta 5)-tubulin gene. The gene displayed the coding structure common to all previously studied vertebrate beta-tubulin genes and was divided into four exon sequences interrupted by three intervening sequences (located between codons 19 and 20, within codon 56, and within codon 93). Comparison of the predicted polypeptide sequence encoded by c beta 5 with those of four other available chicken beta-tubulin sequences revealed that c beta 5 encoded a highly divergent beta-tubulin polypeptide isotype which was distinguished from previously known sequences primarily by two discrete variable sequence domains. However, c beta 5 uniquely shared identity in 16 residue positions with another divergent chicken beta-tubulin gene, c beta 4. These common sequences distinguished c beta 4 and c beta 5 from the remaining three chicken beta-tubulin genes. Analysis of the expression of c beta 5 and c beta 4 revealed a strikingly complementary pattern of gene expression: c beta 5 was expressed in a wide variety of cell and tissue types but not in neurons, whereas c beta 4 expression was detected uniquely in neuronal cells. Overall, these findings suggest the existence of two divergent families of beta-tubulin sequences in the chicken and further raise the possibility that the complementary expression of the c beta 4 and c beta 5 genes may fulfill a requirement for the presence of a divergent beta-tubulin polypeptide isotype in all cell types.
Mol Cell Biol 1986 Dec
PMID:Sequence and expression of the chicken beta 5- and beta 4-tubulin genes define a pair of divergent beta-tubulins with complementary patterns of expression. 302 56

The genomic DNA sequence and deduced amino acid sequence are presented for three Drosophila melanogaster beta-tubulins: a developmentally regulated isoform beta 3-tubulin, the wild-type testis-specific isoform beta 2-tubulin, and an ethyl methanesulfonate-induced assembly-defective mutation of the testis isoform, B2t8. The testis-specific beta 2-tubulin is highly homologous to the major vertebrate beta-tubulins, but beta 3-tubulin is considerably diverged. Comparison of the amino acid sequences of the two Drosophila isoforms to those of other beta-tubulins indicates that these two proteins are representative of an ancient sequence divergence event which at least preceded the split between lines leading to vertebrates and invertebrates. The intron/exon structures of the genes for beta 2- and beta 3-tubulin are not the same. The structure of the gene for the variant beta 3-tubulin isoform, but not that of the testis-specific beta 2-tubulin gene, is similar to that of vertebrate beta-tubulins. The mutation B2t8 in the gene for the testis-specific beta 2-tubulin defines a single amino acid residue required for normal assembly function of beta-tubulin. The sequence of the B2t8 gene is identical to that of the wild-type gene except for a single nucleotide change resulting in the substitution of lysine for glutamic acid at residue 288. This position falls at the junction between two major structural domains of the beta-tubulin molecule. Although this hinge region is relatively variable in sequence among different beta-tubulins, the residue corresponding to glu 288 of Drosophila beta 2-tubulin is highly conserved as an acidic amino acid not only in all other beta-tubulins but in alpha-tubulins as well.
Mol Cell Biol 1987 Jun
PMID:Three Drosophila beta-tubulin sequences: a developmentally regulated isoform (beta 3), the testis-specific isoform (beta 2), and an assembly-defective mutation of the testis-specific isoform (B2t8) reveal both an ancient divergence in metazoan isotypes and structural constraints for beta-tubulin function. 303 52

Sequences of genes for beta-tubulins from many different organisms demonstrate that they encode highly conserved proteins but that these proteins diverge considerably at their carboxyl termini. The patterns of interspecies conservation of this diversity suggest that it may have functional significance. We have taken advantage of the properties of Saccharomyces cerevisiae to test this hypothesis in vivo. The sole beta-tubulin gene of this species is one of the most divergent of all beta-tubulins and encodes 12 amino acids which extend past the end of most other beta-tubulin molecules. We have constructed strains in which the only beta-tubulin gene is an allele lacking these 12 codons. We show here that this carboxy-terminal extension is not essential. The absence of these 12 amino acids had no effect on a number of microtubule-dependent functions, such as mitotic and meiotic division and mating. It did confer dominant supersensitivity to a microtubule-depolymerizing drug.
Mol Cell Biol 1988 Jul
PMID:Diversity among beta-tubulins: a carboxy-terminal domain of yeast beta-tubulin is not essential in vivo. 304 93

We have developed a procedure for determining the rates of mitotic recombination of an interrupted duplication created by integration of transforming plasmid sequences at the benA, beta-tubulin, locus of Aspergillus nidulans. Transformation of a strain carrying a benomyl-resistant benA allele with plasmid AIpGM4, which carries the wild-type benA allele and the pyr4 (orotidine-5'-phosphate decarboxylase) gene of Neurospora crassa, creates an interrupted duplication with plasmid sequences flanked by two benA alleles, one wild type and one benomyl resistant. Such transformants will not grow in the presence of high levels of benomyl. Mitotic recombination causes the loss of the wild-type benA allele or conversion of the wild-type to the mutant allele resulting in nuclei carrying only the benomyl-resistant allele. Conidia containing such nuclei can be selected on media with high benomyl allowing easy quantitation of mitotic recombination. We found that the rate of recombination giving rise to benomyl-resistant conidia was 4.6 x 10(-4). Reciprocal recombination leading to benomyl-resistant conidia lacking plasmid sequences occurred at a rate of 2.0 x 10(-4) and gene conversion leading to benomyl-resistant conidia occurred at a rate of 2.6 x 10(-4). We selected for reciprocal recombination leading to loss of pyr4 sequences on 5-fluoro-orotic acid and used this selection for two-step gene replacement of a mutant benA allele with the wild-type allele.
Mol Gen Genet 1988 Aug
PMID:Mitotic gene conversion, reciprocal recombination and gene replacement at the benA, beta-tubulin, locus of Aspergillus nidulans. 305 84

It has been established that the 90-kilodalton murine heat shock protein, hsp90, is associated with the untransformed, non-DNA-binding form of the glucocorticoid receptor in L cell cytosol. In this work, we show that incubation of L cell cytosol with Affi-Gel-coupled monoclonal antibodies directed against either alpha-tubulin alone or both alpha- and beta-tubulin results in the immune-specific adsorption of hsp90 identified by Western blotting with the AC88 monoclonal antibody. Similarly, the AC88 antibody, which is specific for hsp90, causes the immune-specific isolation of both alpha- and beta-tubulin from hypotonic cytosol. The distribution of hsp90 in cultured Potorous tridactylis kidney cells was examined by indirect immunofluorescence using the AC88 monoclonal as primary antibody. In interphase cells, AC88-dependent fluorescence was distributed like antitubulin antibody-dependent fluorescence in a fibrillar array located in the cytoplasm and around the periphery of the nucleus. In cells undergoing mitosis, AC88 fluorescence was located in the mitotic spindle. These observations suggest that a significant portion of hsp90 is associated with a tubulin-containing complex both in a hypotonic cytosol preparation from mouse fibroblasts and in intact marsupial kidney epithelial cells. The distribution of AC88 fluorescence in interphase Potorous tridactylis kidney cells is similar to the distribution of glucocorticoid receptor demonstrated by Wikstrom, A. C., Bakke, O., Okret, S., Bronnegard, M., and Gustafsson, J. A in rat hepatoma and human uterine cells.
Mol Endocrinol 1988 Aug
PMID:Evidence that the 90-kilodalton heat shock protein is associated with tubulin-containing complexes in L cell cytosol and in intact PtK cells. 306 85

The gene-sized macronuclear DNA of the hypotrichous ciliate Stylonychia lemnae contains one size class of DNA molecules of 1.85 kb (1 kb = 10(3) base-pairs) coding for beta-tubulin. These DNA molecules consist of two different beta-tubulin genes, beta 1 and beta 2, which are amplified to about 150,000 (beta 1) and 30,000 (beta 2) copies per macronucleus. Both genes were cloned and sequenced entirely. The coding sequences of the two molecules (1329 base-pairs including TGA) predict identical amino acid sequences for the proteins and show a nucleotide homology of 97.2%. The nucleotide as well as the encoded amino acid sequences are highly conserved, when compared to beta-tubulin genes from vertebrates. The ciliate-specific codon TAA specifying glutamine is present only in the beta 2-tubulin gene, whereas glutamine is encoded soley by CAA in the beta 1-tubulin gene. The 5' and 3'-non-coding regions of both beta-tubulin genes are similar in length, but differ extremely in nucleotide sequence. Both beta-tubulin genes are transcriptionally active in S. lemnae, although not all putative transcription-regulatory sequences known from higher eukaryotes can be detected within the non-coding regions. The two transcription products localized by S1-mapping experiments show a similar length of about 1.40 kb and transcription seems to be regulated differently for beta 1 and beta 2.
J Mol Biol 1987 Dec 20
PMID:Nucleotide sequence and expression of two beta-tubulin genes in Stylonychia lemnae. 312 2


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