title: Cloning and characterization of Pros45, the Drosophila SUG1 proteasome subunit homolog.
abstract: The proteasome plays essential roles in a variety of cellular processes, including degradation of the bulk of cellular proteins, degradation of short-lived proteins such as cell cycle regulators, generation of antigenic peptides, and mediating programmed cell death. One of the best characterized subunits of the 26S proteasome is encoded by the yeast gene SUG1. We report here the cloning and characterization of the Drosophila homolog of this gene, Pros45. At the protein level, Pros45 is highly conserved with respect to its homologs in a variety of taxa: it shows 74% identity to yeast Sug1; 86% to mouse m56/mSug1/FZA-B; 87% to human Trip1; and 97% to moth 18-56. Using a genomic clone as a probe for in situ hyridization to polytene chromesomes, we demonstrated that Pros45 maps to 19F, near the base of the X chromosome. Use of a pros45 cDNA clone as a probe revealed a second site of hybridization at 99CD. Pros45 mRNA is found in the unfertilized egg and in all cells of the early embryo. By the end of embryogenesis, Pros45 is expressed predominantly in the central nervous system. Targeted expression of Pros45 in a variety of different cells using the Gal4 UAS P-element system failed to generate an overt phenotype. This study provides the foundation for further examination of the role of the 26S proteasome in homeostasis and development in Drosophila.
authors.affiliation: Molecular and Cellular Biology Program, University of Massachusetts, Amherst 01003, USA.
authors.forename: L
authors.initials: L
authors.lastname: Cheng
authors.forename: N
authors.initials: N
authors.lastname: Roemer
authors.forename: K A
authors.initials: KA
authors.lastname: Smyth
authors.forename: J
authors.initials: J
authors.lastname: Belote
authors.forename: J R
authors.initials: JR
authors.lastname: Nambu
authors.forename: L M
authors.initials: LM
authors.lastname: Schwartz
mesh_terms: D000251:Adenosine Triphosphatases; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics*; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology / Q000201:enzymology* / Q000235:genetics*; D010450:Endopeptidases; D005656:Fungal Proteins / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000737:chemistry* / Q000235:genetics*; D046988:Proteasome Endopeptidase Complex; D012097:Repressor Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D002352:Carrier Proteins; D029721:Drosophila Proteins; D005656:Fungal Proteins; D012097:Repressor Proteins; C114506:Rpt6 protein, Drosophila; D029701:Saccharomyces cerevisiae Proteins; D010450:Endopeptidases; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; D000251:Adenosine Triphosphatases; C069670:RPT6 protein, S cerevisiae