A multicopy suppressor of nin1-1 of the yeast Saccharomyces cerevisiae is a counterpart of the Drosophila melanogaster diphenol oxidase A2 gene, Dox-A2.
NIN1 is an essential gene for growth of the yeast Saccharomyces cerevisiae and was recently found to encode a component of the regulatory subunit of the 26S proteasome. The nin1-1 mutant is temperature sensitive and its main defect is in G1/S progression and G2/M progression at non-permissive temperatures. One of the two multicopy suppressors of nin1-1, SUN2 (SUppressor of Nin1-1), was found to encode a protein of 523 amino acids whose sequence is similar to those of Drosophila melanogaster diphenol oxidase A2 and the mouse mast-cell Tum(-) transplantation antigen, P91A. The C-terminal half of Sun2p was found to be functional as Sun2p at 25 degrees C, 30 degrees C, and 34 degrees C but not at 37 degrees C. The open reading frame (ORF) of the Drosophila diphenol oxidase A2 gene (Dox-A2) was obtained from a lambda phage cDNA library using the polymerase chain reaction technique. The Dox-A2 ORF driven by the TDH3 promoter complemented the phenotype of a strain deleted for sun2. This Dox-A2-dependent strain was temperature sensitive and accumulated dumb-bell-shaped cells, with an undivided nucleus at the isthmus, after temperature upshift. This morphology is similar to that of nin1-1 cells kept at a restrictive temperature. These results suggest that SUN2 is a functional counterpart of Dox-A2 and that these genes play a pivotal role in the cell cycle in each organism.
Kawamura
M
M
Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan.
Kominami
K
K
Takeuchi
J
J
Toh-e
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004156:Catechol Oxidase / Q000235:genetics*; D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004331:Drosophila melanogaster / Q000201:enzymology* / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D006649:Histocompatibility Antigens / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010641:Phenotype; D011401:Promoter Regions, Genetic; D046988:Proteasome Endopeptidase Complex; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic; D013696:Temperature
D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D005656:Fungal Proteins; D006649:Histocompatibility Antigens; C074096:RPN12 protein, S cerevisiae; C403291:RPN3 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C070850:transplantation antigen P91A, mouse; D004156:Catechol Oxidase; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D046988:Proteasome Endopeptidase Complex