Molecular cloning and expression of a Tetrahymena pyriformis ubiquitin fusion gene coding for a 53-amino-acid extension protein.
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.
Neves
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AM
Laboratório Genética Molecular, Instituto Gulbenkian de Ciência, Oeiras, Portugal.
Guerreiro
P
P
Miquerol
L
L
Rodrigues-Pousada
C
C
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D016054:DNA, Protozoan / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D011498:Protein Precursors / Q000235:genetics*; D015800:Protozoan Proteins / Q000235:genetics*; D016053:RNA, Protozoan / Q000235:genetics; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013769:Tetrahymena pyriformis / Q000235:genetics*; D014452:Ubiquitins / Q000235:genetics*
D016054:DNA, Protozoan; D011498:Protein Precursors; D015800:Protozoan Proteins; D016053:RNA, Protozoan; D014452:Ubiquitins; C045677:ubiquitin precursor