High impact information on RPN12

• Cytokinin growth responses in Arabidopsis involve the 26S proteasome subunit RPN12 [1].
• In yeast, RPN12 is necessary for the G1/S and G2/M transitions of the cell cycle, phases that have been shown to be under cytokinin control in plants [1].
• In striking contrast, Sic1 turnover is severely impaired by a temperature-sensitive mutation in RPN12/NIN1, encoding another essential RP subunit [2].
• The SEN3 also was identified in a synthetic lethal screen with the nin1-1 mutant, a temperature-sensitive mutant of NIN1 [3].
• The deduced amino acid sequences of both mts3+ and NIN1 show homology to peptide sequences obtained from subunit 14 of the 26 S protease purified from bovine or human cells [4].

Biological context of RPN12

• Genetic evidence for interaction between components of the yeast 26S proteasome: combination of a mutation in RPN12 (a lid component gene) with mutations in RPT1 (an ATPase gene) causes synthetic lethality [5].
• We identified a new essential gene of Saccharomyces cerevisiae, designated NIN1 (nuclear integrity) [6].
• In this study, a genetic event occurring in the nin1-1 mutant was found to be a frameshift mutation, resulting in a truncated protein smaller than the wild-type Nin1 protein [7].
• Disruption of NIN1 resulted in cell death; however, a dead spore clone contained about 30 dead cells, indicating that spores that received the disrupted nin1 allele divided approximately five times before their death [6].
• NIN1 is mapped on chromosome VI, 16 cM centromere-distal to PHO4 [6].

Physical interactions of RPN12

• We propose that this region is necessary for Rpt1 to interact with Rpn12 [5].

Other interactions of RPN12

• The resultant precipitate contained Nin1p, Sun1p, TBP1, and the 20S proteasome [8].
• First, overexpression of two components of the 19 S RP, namely Pad1/Rpn11 and Mts3/Rpn12, rescued the temperature-sensitive growth defect of the dss1 mutant [9].

Analytical, diagnostic and therapeutic context of RPN12

• We found dotted structures in the cytoplasm of the wild-type cells by indirect immunofluorescence microscopy using the anti-Nin1 antibody [7].
• Western blotting using anti-Nin1 antibody reveals that NIN1 produces a doublet consisting of 32 and 34 kDA whose size is close enough to that calculated from the predicted amino acid sequence of Nin1 [6].

References