C. elegans dss-1 is functionally conserved and required for oogenesis and larval growth.
BACKGROUND
Dss1 (or Rpn15) is a recently identified subunit of the 26S proteasome regulatory particle. In addition to its function in the protein degradation machinery, it has been linked to BRCA2 (breast cancer susceptibility gene 2 product) and homologous DNA recombination, mRNA export, and exocytosis. While the fungal orthologues of Dss1 are not essential for viability, the significance of Dss1 in metazoans has remained unknown due to a lack of knockout animal models.


RESULTS
In the current study deletion of dss-1 was studied in Caenorhabditis elegans with a dss-1 loss-of-function mutant and dss-1 directed RNAi. The analysis revealed an essential role for dss-1 in oogenesis. In addition, dss-1 RNAi caused embryonic lethality and larval arrest, presumably due to loss of the dss-1 mRNA maternal contribution. DSS-1::GFP fusion protein localised primarily in the nucleus. No apparent effect on proteasome function was found in dss-1 RNAi treated worms. However, expression of the C. elegans dss-1 in yeast cells deleted for its orthologue SEM1 rescued their temperature-sensitive growth phenotype, and partially rescued the accumulation of polyubiquitinated proteins in these cells.


CONCLUSIONS
The first knockout animal model for the gene encoding the proteasome subunit DSS-1/Rpn15/Sem1 is characterised in this study. In contrast to unicellular eukaryotes, the C. elegans dss-1 encodes an essential protein, which is required for embryogenesis, larval growth, and oogenesis, and which is functionally conserved with its yeast and human homologues.
Pispa
Johanna
J
Cellular Biotechnology Research Program, Institute of Biotechnology, University of Helsinki, Finland. johanna.pispa@helsinki.fi
Palmén
Susanna
S
Holmberg
Carina I
CI
Jäntti
Jussi
J
D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development* / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005298:Fertility / Q000235:genetics / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018390:Gene Targeting; D017238:Genes, Helminth; D007814:Larva / Q000254:growth & development; D008297:Male; D009154:Mutation; D009866:Oogenesis / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000502:physiology; D034622:RNA Interference; D018510:RNA, Helminth / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D017931:DNA Primers; D018510:RNA, Helminth; D012333:RNA, Messenger; C117424:SEM1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease