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

Tubulin was estimated to account for 16.3% and 0.25% of protein in rat brain and Nippostrongylus brasiliensis supernatants, respectively. Tubulin from N. brasiliensis and rat brain have been partially purified using polylysine agarose chromatography and high performance liquid chromatography on a gel permeation column. Western blots with alpha- and beta-tubulin monoclonal antibodies confirmed the presence of tubulin in different fractions. The mobility of N. brasiliensis tubulin on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was similar to that of rat brain tubulin. The isoelectric range for N. brasiliensis alpha- and beta-tubulin isoforms was pH 5.4-4.8 and pH 4.8-4.7, respectively. However, for rat brain the corresponding ranges were pH 5.4-4.9 and pH 5.0-4.6, respectively. Western blots with anti-tubulin monoclonal antibodies revealed 8 isoforms of alpha-tubulin and 3 isoforms of beta-tubulin for N. brasiliensis and 14-15 and 7-8 isoforms for rat brain alpha- and beta-tubulins, respectively. Different peptide maps were obtained for N. brasiliensis tubulin compared with rat brain tubulin.
Mol Biochem Parasitol 1988 Jun
PMID:Comparison of the properties of tubulin from Nippostrongylus brasiliensis with mammalian brain tubulin. 341 74

We have studied the fundamentals of gene expression in the protozoan parasite Toxoplasma gondii by analyzing, in detail, the genes encoding alpha- and beta-tubulin. Southern analysis and quantitation studies reveal that, unlike in other organisms studied thus far, both these genes are present as single copies in the haploid Toxoplasma genome. Sequencing of these genes indicates that they both contain multiple introns with conserved 5' and 3' splice site signals. We have found that HeLa cell nuclear extracts are able to accurately splice a Toxoplasma pre-mRNA construct. We have mapped, for the alpha-tubulin gene, the exact site of transcription initiation and the approximate site of poly A addition by primer extension and RNase protection assays. Trans-splicing, as demonstrated in the Kinetoplastida, is not involved in the formation of the mature alpha-tubulin transcript in T. gondii.
Mol Biochem Parasitol 1988 Jun
PMID:The alpha- and beta-tubulins of Toxoplasma gondii are encoded by single copy genes containing multiple introns. 341 77

We evaluated the extent to which muscle-specific genes display identical patterns of mRNA accumulation during human myogenesis. Cloned satellite cells isolated from adult human skeletal muscle were expanded in culture, and RNA was isolated from low- and high-confluence cells and from fusing cultures over a 15-day time course. The accumulation of over 20 different transcripts was compared in these samples with that in fetal and adult human skeletal muscle. The expression of carbonic anhydrase 3, myoglobin, HSP83, and mRNAs encoding eight unknown proteins were examined in human myogenic cultures. In general, the expression of most of the mRNAs was induced after fusion to form myotubes. However, several exceptions, including carbonic anhydrase and myoglobin, showed no detectable expression in early myotubes. Comparison of all transcripts demonstrated little, if any, identity of mRNA accumulation patterns. Similar variability was also seen for mRNAs which were also expressed in nonmuscle cells. Accumulation of mRNAs encoding alpha-skeletal, alpha-cardiac, beta- and gamma-actin, total myosin heavy chain, and alpha- and beta-tubulin also displayed discordant regulation, which has important implications for sarcomere assembly. Cardiac actin was the only muscle-specific transcript that was detected in low-confluency cells and was the major alpha-actin mRNA at all times in fusing cultures. Skeletal actin was transiently induced in fusing cultures and then reduced by an order of magnitude. Total myosin heavy-chain mRNA accumulation lagged behind that of alpha-actin. Whereas beta- and gamma-actin displayed a sharp decrease after initiation of fusion and thereafter did not change, alpha- and beta-tubulin were transiently induced to a high level during the time course in culture. We conclude that each gene may have its own unique determinants of transcript accumulation and that the phenotype of a muscle may not be determined so much by which genes are active or silent but rather by the extent to which their transcript levels are modulated. Finally, we observed that patterns of transcript accumulation established within the myotube cultures were consistent with the hypothesis that myoblasts isolated from adult tissue recapitulate a myogenic developmental program. However, we also detected a transient appearance of adult skeletal muscle-specific transcripts in high-confluence myoblast cultures. This indicates that the initial differentiation of these myoblasts may reflect a more complex process than simple recapitulation of development.
Mol Cell Biol 1987 Nov
PMID:Differential patterns of transcript accumulation during human myogenesis. 343 50

Under conditions in which cytoplasmic accumulation of HeLa cell mRNAs has been blocked by adenovirus infection, hsp70 family mRNAs are transported from the nucleus to the cytoplasm at near normal efficiency subsequent to heat shock. Heat shock does not reverse the general virus-induced block to host cell mRNA transport. The heat shock mRNAs are translated within the cytoplasm of the infected cell but at substantially reduced efficiency compared with that of uninfected cells. Thus, the hsp70 family of mRNAs can escape the transport block but not the translational block instituted late after adenovirus infection. The beta-tubulin gene family is induced by the viral E1A gene after infection, and its mRNAs also accumulate in the cytoplasmic compartment. Given these two examples, it seems likely that the process of transcriptional induction allows the resulting mRNA to escape the viral block of transport.
Mol Cell Biol 1987 Dec
PMID:Induced heat shock mRNAs escape the nucleocytoplasmic transport block in adenovirus-infected HeLa cells. 343 95

We identified four mutations in two previously undescribed loci involved in microtubule function in Aspergillus nidulans as extragenic suppressors of benA33, a heat-sensitive beta-tubulin mutation. Three of the four mutations map to a locus closely linked to riboB on linkage group VIII; we designated this locus mipA (for microtubule-interacting protein). We were not able to map the remaining suppressor because of chromosomal rearrangements. However, since it recombines with riboB at a significantly higher frequency than the mipA alleles, it is unlikely to be in mipA; thus, we designated it mipB1. The mip mutations are not allelic to the previously identified loci that encode alpha- and beta-tubulin, and it is likely that mipA and mipB encode previously unidentified nontubulin proteins involved in microtubule function. Each of the mip mutations suppresses the heat sensitivity conferred by benA33 and suppresses the blockage of nuclear division and movement conferred by this mutation at high temperatures. Interactions between mipA and benA are allele specific. All of the mipA mutations are cryptic in a wild-type benA background but cause cold sensitivity in combination with benA33. These mutations also confer cold sensitivity in combination with benA31 and benA32 and reduce the resistance conferred by these mutations to the antimicrotubule agent benomyl but do not suppress the heat sensitivity conferred by these alleles. Finally, the mipA alleles suppress the heat sensitivity conferred by benA11, benA17, and benA21 but do not confer cold sensitivity in combination with these alleles.
Mol Cell Biol 1986 Aug
PMID:Isolation of mip (microtubule-interacting protein) mutations of Aspergillus nidulans. 353 28

A minimum of 22 chromosomes were found in all Leishmania donovani stocks examined by orthogonal field alternation gel electrophoresis (OFAGE). Chromosome sizes ranged from approximately 270 to 4000 kb. Certain chromosomes were polymorphic in size between stocks and chromosomes present in some stocks had no apparent equivalent in others. Specific polymorphisms were useful in distinguishing the subspecies L. d. donovani, L. d. infantum and L. d. chagasi and African L. donovani stocks but there were karotypic differences within these taxa. Radiolabelled DNA derived from whole chromosomes was hybridised to OFAGE Southern blots. Chromosome 1 of L. d. donovani was homologous to two larger chromosomes in all stocks. Chromosome 2 of certain L. d. chagasi and L. d. infantum stocks was homologous to both chromosomes 2 and 3 of L. d. donovani: this suggested that translocation between chromosomes may have contributed to the size polymorphisms. The smallest chromosome seen (270 kb) was unique to the African stock HU3. It was not homologous to small chromosomes in L. d. donovani, L. d. infantum or L. d. chagasi. The small chromosome did hybridise to two small chromosomes in another African stock, Khartoum, and to a large chromosome present in all stocks. The beta-tubulin gene was mapped to chromosomes 21/22, 13 and 7 with strongest hybridisation to 21/22. alpha-Tubulin was mapped to chromosomes 9. The alpha- and beta-tubulin arrangement was highly conserved.
Mol Biochem Parasitol 1987 Jul
PMID:Chromosome size polymorphisms of Leishmania donovani. 362 71

Eight strains of Chinese hamster ovary (CHO) cells having an assembly-defective beta-tubulin were found among revertants of strain Cmd 4, a mutant with a conditional lethal mutation in a beta-tubulin gene (F. Cabral, M. E. Sobel, and M. M. Gottesman, Cell 20:29-36, 1980). The altered beta-tubulins in these strains have electrophoretically silent alterations or, in some cases, an increase or a decrease in apparent molecular weight based on their migration in two-dimensional gels. The identity of these variant proteins as beta-tubulin was confirmed by peptide mapping, which also revealed the loss of distinct methionine-containing peptides in the assembly-defective beta-tubulins of lower apparent molecular weight. The altered mobility of these beta-tubulin polypeptides was not the result of a posttranslational modification, since the altered species could be labeled in very short incubations with [35S]methionine and were found among in vitro-translated polypeptides by using purified mRNA. In at least one strain, an altered DNA restriction fragment could be demonstrated, suggesting that an alteration occurred in one of the structural genes for beta-tubulin. Assembly-defective beta-tubulin was unstable and turned over with a half-life of only 1 to 2 h in exponentially growing cells. This rapid degradation of a tubulin gene product resulted in approximately 30% lower steady-state levels of both alpha- and beta-tubulin yet did not affect the growth rate of the cells or the distribution of the microtubules as judged by immunofluorescence microscopy. These results argue that CHO cells possess a beta-tubulin gene product that is not essential for survival.
Mol Cell Biol 1987 Aug
PMID:Mutations affecting assembly and stability of tubulin: evidence for a nonessential beta-tubulin in CHO cells. 367 Feb 90

Processed pseudogenes arise via unimolecular events that result in the integration of nonfunctional (and therefore non-selected) regions of DNA into the germ line. The sequence of such pseudogenes can be used as a novel form of evolutionary clock: the older a particular pseudogene, the more mutations it has acquired relative to the selectively constrained functional gene from which it was originally derived. We have used specific beta-tubulin gene probes to assay for the presence of fully sequenced processed pseudogenes in genomic DNA from various hominoid species. The data suggest that orangutan is more closely related to human, chimpanzee and gorilla than is generally believed.
J Mol Biol 1986 Feb 20
PMID:Tubulin pseudogenes as markers for hominoid divergence. 371 38

The tubulin genes of Trypanosoma brucei are located in a single, tightly packed cluster of ten tandemly arranged alternating alpha and beta-genes. No tubulin genes are detected outside the clustered array. Therefore, the cluster can be assumed to be the locus of tubulin gene expression. Single bands of alpha and beta-tubulin mRNAs are observed in cultured procyclic as well as in bloodstream trypanosomes. Both alpha and beta-tubulin mRNAs have distinct 5' termini, which carry a 35-nucleotide mini-exon sequence. The 3' termini of both mRNA populations are heterogeneous.
J Mol Biol 1986 Apr 05
PMID:Tubulin mRNAs of Trypanosoma brucei. 373 27

The DNA karyotypes of three species and several subspecies of New World Leishmania were found to be distinct. The karyotypes were more similar among closely related isolates than among more distantly related groups. Two classes of chromosomal DNA differences were detected among stocks; +/- 50 kb size differences among DNAs, some of which were shown to contain homologous sequences, and DNAs having no obvious corresponding chromosomal DNA in other isolates. A total of 14-24 chromosomal DNA bands were resolved, depending on the isolate, but densitometric analyses suggest that these isolates contain 26-33 distinct DNA molecules. These molecules total about 2.5 X 10(7) bp, a substantial fraction of the genomic DNA. The chromosomal DNA locations of gene sequences homologous to alpha- and beta-tubulin, ribosomal RNA, thymidylate synthetase-dihydrofolate reductase, and the H-region sequence were determined. The homologous sequences were located on chromosomal DNAs of similar, but not identical sizes among different stocks. We also found species- and some subspecies-specific beta-tubulin chromosomal loci. We conclude that the DNA karyotype is useful for stock identification, taxonomy, and gene localization in Leishmania. Its potential for identifying the species and subspecies in natural infections appears less useful unless applied in conjunction with specific hybridization probes.
Mol Biochem Parasitol 1986 Sep
PMID:Molecular karyotype of species and subspecies of Leishmania. 376 94


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