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

Thirteen and 10 sequences of the Alu family of repeated DNA elements found within the human thymidine kinase and beta-tubulin genes, respectively, were compared. These genes have approximately five times the expected density of Alu family members. The consensus sequence that could be drawn from these 23 Alu family members would differ slightly from others drawn from random Alu family sequences but only at very heterogeneous positions. The different Alu family members do show different pairwise percentage identities, with approximately 15% (7 of 48 Alu family members analyzed) of them clearly representing a separate subfamily of sequences. This analysis also confirms the species-specific differences between human and the prosimian Galago crassicaudatus Alu family members. These data are consistent with both the origin of these sequences in primates less than 65-70 Myr ago and amplification since that time to their present 500,000 copies. The data do not show any special relationships among densely clustered Alu family members.
Mol Biol Evol 1987 Jan
PMID:Clustering and subfamily relationships of the Alu family in the human genome. 312 13

Sea urchin and rodent genomes have been posited to evolve rapidly as indicated by divergences in single copy nuclear DNA sequences. We have examined whether the synonymous substitution rates of three highly conserved genes, beta-tubulin, histone H4, and histone H3, adhere to these high genomic substitution rates by comparing sequences between two sea urchins, Strongylocentrotus purpuratus and Lytechinus pictus, and between rodents and humans. Whereas the rate of change between the 3' untranslated regions of the beta-tubulin cDNA of S. purpuratus (Sp-beta 1), sequenced in this study, and of L. pictus (Lp-beta 3) was consistent with the overall rate of change estimated from previous DNA hybridization results between these species, the synonymous substitution rates for the carboxyl domains of these beta-tubulins, as well as for the late histones H4 and H3, were significantly depressed. In contrast, synonymous nucleotide substitution rates between rodents and between rodent and human for the carboxyl domain proper of identical beta-tubulin isotypes and for histone H4 and H3.1 did not differ from the overall rate of change for the rodent genomes. Moreover, an analysis of paralogous human and mouse beta-tubulin sequences supported the conclusion that the synonymous substitution rates in the mouse were higher than those in the human. Differences in constraint on evolutionary change were not evident strictly from the conserved amino acid sequences and base compositions of these genes. Other constraining influences seemed more relevant to the departure of the synonymous substitution rates of the sea urchin beta-tubulin and histone coding regions from the average genomic rate.
J Mol Evol 1988
PMID:Synonymous nucleotide substitution rates of beta-tubulin and histone genes conform to high overall genomic rates in rodents but not in sea urchins. 313 88

Macronuclear DNA of the ciliate Tetrahymena pyriformis contains only one size class of fragments coding for alpha-tubulin, alpha TT. We have isolated alpha TT from a partial plasmid library, using Chlamydomonas reinhardtii alpha-tubulin gene as a probe. This gene as well as the two beta-tubulin genes, beta TT1 and beta TT2, have been sequenced. None of these genes contains introns and all use TGA as the stop codon. In the coding region of the two beta-tubulin genes, there are several TAA and TAG stop codons that probably code for glutamine. The codon usage is very biased. Regions flanking the tubulin coding sequences are A + T-rich (75%) and quite different among themselves. In these regions there are several putative transcription-regulatory sequences. Nuclear transcripts begin and terminate at multiple sites. The beta-tubulin proteins differ only in two amino acid residues. Primary structure of Tetrahymena tubulins as well as their hydropathy indexes show a high degree of homology with tubulins from other organisms. Two-dimensional electrophoretic analysis of the ciliary tubulins shows the presence of eight alpha-tubulins and four beta-tubulins. The alpha-tubulins migrate faster than the beta-tubulins, in contrast with what happens with brain tubulins. We suggest that there are several alpha- and beta-tubulin isoforms and the migratory inversion observed may be due to post-translational modifications.
J Mol Biol 1988 Aug 05
PMID:Sequence of one alpha- and two beta-tubulin genes of Tetrahymena pyriformis. Structural and functional relationships with other eukaryotic tubulin genes. 313 85

The transition from the promastigote stage to the amastigote stage in Leishmania appears to involve a sequence of steps which enable the parasite to adapt to its new environment. In this study, transformation from the promastigote to an amastigote-like stage was induced by temperature elevation and the effects on protein synthesis and the mRNA population were analyzed. Whereas significant changes in the polypeptide complement of the cell were observed, few, if any, changes were seen at the level of the mRNAs as determined by translation in a cell-free system. Increasing the growth temperature caused a rapid cessation of beta-tubulin synthesis but the abundance and sizes of mRNAs specific for beta-tubulin were unaltered. These data suggest that the regulation of beta-tubulin under these conditions is occurring at the level of translation.
Mol Biochem Parasitol 1988 Aug
PMID:Effects of temperature elevation on mRNA and protein synthesis in Leishmania mexicana amazonensis. 317 31

Genomic clones encoding two Volvox beta-tubulin genes have been isolated and shown to represent the only two beta-tubulin genes in the genome. Restriction fragment length polymorphism analysis was used to demonstrate that the two genes are genetically linked. One of these genes was sequenced and the mRNA start site(s) determined by primer extension. A comparison of its sequence to those of the two beta-tubulin genes of Chlamydomonas revealed: (1) a high degree of conservation of the coding region, with the predicted amino acid sequence differing only in the C-terminal residue; (2) extensive sequence conservation in the 5' untranslated leader region and a 16 bp (putative regulatory) sequence in the promoter region; (3) the same number and location of introns, with a short region of homology in intron 1, but little significant homology in introns 2 and 3.
Mol Gen Genet 1988 Aug
PMID:Organization and structure of Volvox beta-tubulin genes. 318 5

RNA was isolated from uteri of immature rats before and after estrogen treatment. The concentration of histone mRNA was analyzed by Northern hybridization and compared with messenger RNA concentration of alpha-actin, beta-actin, and beta-tubulin. Steady state levels of common histone mRNAs did not change up to 9 h after hormone administration. After that time the histone mRNA levels increased significantly and reached a maximum at 18 h, several hours later than the time of maximal histone protein biosynthesis induced by estrogen. The concentration of control mRNAs (alpha- and beta-actin and beta-tubulins) increased shortly after estradiol injection and reached a peak at 9 h. These results show that the pattern of histone gene expression induced by estrogen has some features similar to those observed during embryogenesis.
Mol Endocrinol 1988 Aug
PMID:Estrogen effects on histone messenger ribonucleic acid levels in the rat uterus. 321 Nov 55

We have mapped 17 extragenic suppressors of benA33, a heat-sensitive beta-tubulin mutation of Aspergillus nidulans, to the tubA alpha tubulin locus. Fifteen of these tubA mutations cause cold sensitivity in a genetic background with benA33 and appear to cause lethality in a background with the wild-type benA allele. We examined the microtubule-mediated processes, nuclear division and nuclear migration, in seven different cold-sensitive double mutants, each carrying benA33 and a different cold-sensitive tubA allele. Nuclear division and migration were inhibited at a restrictive temperature in each case, suggesting that cold sensitivity is due to the inhibition of microtubule function at low temperatures. A single allele, tubA4, suppressed the heat sensitivity conferred by benA33 but did not confer cold sensitivity in a benA33 background, however in a wild-type benA background, tubA4 conferred supersensitivity to antimicrotubule agents and weak cold sensitivity. TubA4 did not suppress the heat sensitivity conferred by two other benA alleles. The cold sensitivity conferred by tubA4 was suppressed by the microtubule stabilizing agent deuterium oxide, and the suppression of heat sensitivity conferred by four other tubA mutations was reversed by deuterium oxide. These results suggest that these mutations may affect hydrophobic interactions between alpha- and beta-tubulin.
Mol Gen Genet 1987 Jun
PMID:Conditionally lethal tubA alpha-tubulin mutations in Aspergillus nidulans. 330 5

Zinc-induced tubulin sheets were grown at pH values of 5.7 and 6.4 from porcine brain tubulin purified by phosphocellulose chromatography as well as from microtubule protein containing tubulin plus 20% (w/w) unfractionated microtubule-associated proteins (MAPs). Electron micrographs of negatively stained sheets were analyzed by a combination of real space cross-correlation and Fourier space methods, providing two-dimensional reconstructions to approximately 16 A resolution. The reconstructed images revealed that the protofilaments comprising zinc-induced sheets are composed of two clearly distinguishable alternating subunits, presumably corresponding to the alpha- and beta-tubulin monomers, whose morphologies are not significantly influenced by pH or the presence of MAPs during sheet assembly. Sheets assembled at pH 5.7, either with or without MAPs, were divided into two domains by a protofilament discontinuity which was not present in sheets assembled at pH 6.4, and displayed a 2.4 A reduction of the interprotofilament distance in projection relative to sheets assembled at pH 6.4. We conclude that morphological differences between tubulin subunits represent intrinsic structural features not contributed by MAPs, and that pH is more important than MAP content in influencing the lattice parameters of zinc-induced sheets.
J Ultrastruct Mol Struct Res 1988 Jan
PMID:Conservation of tubulin alpha-beta differences in zinc-induced sheets with variations in pH and microtubule-associated protein content. 335 54

In chicken, beta-tubulin is encoded by a family of seven genes. We have now isolated and sequenced overlapping cDNA clones corresponding to gene c beta 7 (previously designated c beta 4'), the only chicken beta-tubulin not previously characterized. The inferred amino acid sequence of c beta 7 tubulin is identical with the class I beta-tubulin isotype found in human, mouse and rat. Moreover, c beta 7 is highly expressed in almost all tissue and cell types in chicken, a pattern similar to those of the genes for class I beta-tubulin isotypes in other vertebrates. Comparison of the complete family of chicken beta-tubulin gene sequences reveals that the heterogeneity of beta-tubulin polypeptides encoded in a higher eukaryote is confined to six distinct beta-tubulin isotypes. Five of these are members of evolutionarily conserved isotypic classes (I to V), whereas the sixth represents a divergent erythroid-specific tubulin whose sequence has not been conserved.
J Mol Biol 1988 Feb 05
PMID:Sequence of chicken c beta 7 tubulin. Analysis of a complete set of vertebrate beta-tubulin isotypes. 335 37

The nuclear run-on technique was used to measure the rate of transcription of flagellar genes during the differentiation of Naegleria gruberi amebae into flagellates. Synthesis of mRNAs for the axonemal proteins alpha- and beta-tubulin and flagellar calmodulin, as well as a coordinately regulated poly(A)+ RNA that codes for an unidentified protein, showed transient increases averaging 22-fold. The rate of synthesis of two poly(A)+ RNAs common to amebae and flagellates was low until the transcription of the flagellar genes began to decline, at which time synthesis of the RNAs found in amebae increased 3- to 10-fold. The observed changes in the rate of transcription can account quantitatively for the 20-fold increase in flagellar mRNA concentration during the differentiation. The data for the flagellar calmodulin gene demonstrate transcriptional regulation for a nontubulin axonemal protein. The data also demonstrate at least two programs of transcriptional regulation during the differentiation and raise the intriguing possibility that some significant fraction of the nearly 200 different proteins of the flagellar axoneme is transcriptionally regulated during the 1 h it takes N. gruberi amebae to form visible flagella.
Mol Cell Biol 1988 Jun
PMID:Transcriptional regulation of coordinate changes in flagellar mRNAs during differentiation of Naegleria gruberi amebae into flagellates. 340 5


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