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Query: UNIPROT:P62988 (Ubiquitin)
 4,326 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The genome of Tetrahymena pyriformis has been shown to contain a ubiquitin multigene family consisting of several polyubiquitin genes and at least one ubiquitin fusion gene. We report here the isolation and characterization of one genomic clone (pTU11), that encodes a ubiquitin extension protein. A comparison of the predicted amino acid sequence of the ubiquitin extension protein gene of T. pyriformis with those from other organisms indicated a high degree of homology. However, the Tetrahymena ubiquitin extension protein contains 53 and not 52 amino acids. This feature is different from all ubiquitin 52-amino-acid extension protein genes thus far sequenced. Furthermore, we found an array of four cysteine residues similar to those found in nucleic acid binding proteins. Also, the C-terminal sequence possesses a conserved motif which may represent a nuclear translocation signal. The ubiquitin 53-amino-acid extension protein gene encodes the smallest class of ubiquitin mRNAs in T. pyriformis.
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PMID:Molecular cloning and expression of a Tetrahymena pyriformis ubiquitin fusion gene coding for a 53-amino-acid extension protein. 166 May 64

The presence of ubiquitin in ciliates was first demonstrated in Tetrahymena pyriformis. One clone--pTU2--presents two incomplete open reading frames and the putative polyubiquitin genes have been shown to be highly similar to those of other organisms. To further analyze the organization of this multigene family, several fragments of macronuclear DNA were cloned. We report here the isolation and characterization of one genomic clone (pTU20) that encodes a polyubiquitin gene (TU20) with five tandem repeats and presenting only one extra triplet CAA (Gln) upstream from the TGA. The promoter region of TU20 also presents a consensus heat shock element. The specific detection of RNA species with a synthetic oligonucleotide probe reveals that it corresponds to the 1.8 kb mRNA species whose expression is increased by temperature stress.
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PMID:The macronuclear polyubiquitin gene of the ciliate Tetrahymena pyriformis. 166 85

Ubiquitin (Ubi) genes encode two types of fusion proteins: polyUbi with a varying number of direct repeats of Ubi, and Ubi-tail fusions with long or short basic C-terminal extensions. A barley (Hordeum vulgare) genomic clone has been isolated with two very similar, intronless genes encoding monoUbi-long-tail fusion peptides. The genes are arranged as direct repeats separated by 3 kb of DNA and account for two of the probable three long-tail genes in the haploid barley genome. Both genes are active and give rise to messengers about 800 nt long. The sequence of the encoded Ubi moieties is identical to the sequence of Ubi repeats of polyUbi precursors from barley and other plants. The basic tails of the peptides are 79 aa long and 71-72% homologous to corresponding sequences from yeast and man. Recently, it was found that the long and short tails are ribosomal proteins in yeast [Finley et al., Nature 338 (1989) 394-401] and the evolutionary conservation of the structure of the Ubi-tail fusion genes suggests that they serve the same function in plants. The similarity between yeast and barley Ubi-long-tail fusion genes may extend to the regulatory regions, since upstream activating sites characteristic of ribosomal protein-encoding genes in yeast (UASrpg) were found in the barley genes.
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PMID:Two ubiquitin-long-tail fusion genes arranged as closely spaced direct repeats in barley. 170 48

A polyubiquitin clone (ubi7) was isolated from a potato (Solanum tuberosum) genomic library using a copy-specific probe from a stress-induced ubiquitin cDNA. The genomic clone contained a 569-bp intron immediately 5' to the initiation codon for the first ubiquitin-coding unit. Two chimeric beta-glucuronidase (GUS) fusion transgenes were introduced into potato. The first contained GUS fused to a 1156-bp promoter fragment containing only 5' flanking and 5' untranslated sequences from ubi7. The second transgene contained GUS translationally fused to the carboxy terminus of the first ubiquitin-coding unit and thus included the intron present in the 5' untranslated region of the polyubiquitin gene. Both ubi7-GUS transgenes were activated by wounding in tuber tissue and in leaves by application of exogenous methyl jasmonate. They were also expressed constitutively in the potato tuber peel (outer 1-2 mm). Both transgenes were actively expressed in mature leaves. Exceptionally high levels of expression were observed in senescent leaves. Transgenic clones containing the ubi7 intron and the first ubiquitin-coding unit showed GUS expression levels at least 10 times higher than clones containing GUS fused to the intronless promoter.
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PMID:Isolation of a polyubiquitin promoter and its expression in transgenic potato plants. 853 96

Using a tobacco ubiquitin cDNA clone as a probe, a genomic clone in EMBL3 coding for a tobacco polyubiquitin protein was isolated. Southern blot hybridization of the genomic clone with the cDNA clone identified a BamHI/EcoRI fragment of 2.5 kb to contain the coding region of polyubiquitin, and thus the fragment was subcloned into a plasmid vector. Nucleotide sequence determination of the clone identified an open reading frame for the four head-to-tail repeats of ubiquitin monomer of 76 amino acids interrupted by an intron sequence of 55 nucleotides. The four ubiquitin units were completely conserved except for the extra glutamine at the carboxy terminus of the last ubiquitin monomer. At the 5'-region upstream of the open reading frame, a sequence of 630 nucleotides was determined. In this region, well-known regulatory sequences such as the CCAAT box, TATA box and heat-shock elements could not be located; instead, a region very rich in C and T and repeats of CA was noticed. In the 3'-downstream region of the open reading frame, a sequence of 474 nucleotides was determined which contained putative polyadenylation signals and a GU-rich region.
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PMID:Structure of a polyubiquitin gene in Nicotiana tabacum. 957 40