Nuclear pore complex clustering and nuclear accumulation of poly(A)+ RNA associated with mutation of the Saccharomyces cerevisiae RAT2/NUP120 gene

摘要: To identify genes involved in the export of messenger RNA from nucleus to cytoplasm, we used an situ hybridization assay screen temperature-sensitive strains Saccharomyces cerevisiae. This identified those which accumulated poly(A)+ their nuclei when shifted non-permissive temperature 37 degrees C. We describe here properties yeast carrying mutations RAT2 gene (RAT - ribonucleic acid trafficking) and cloning gene. Only a low percentage cells rat2-1 allele showed nuclear accumulation cultured at 15 or 23 C, but within 4 h shift nonpermissive approximately 80% cells. No defect was seen import reporter protein bearing localization signal. Nuclear pore complexes (NPCs) are distributed relatively evenly around envelope wild-type In either rat2-2 allele, NPCs were clustered together into one few regions envelope. clustering constitutive property mutant remained crude isolated cells, indicating that these clusters not able redistribute separated cytoplasmic components. Electron microscopy revealed frequently found protuberance often located close spindle pole body. The encodes 120-kD without similarity other known proteins. It essential for growth only high could be suppressed by presence osmolarity media containing 1.0 M sorbitol 0.9 NaCl. phenotypes disruption very similar with alleles. Epitope tagging show Rat2p is periphery co-localizes NPC proteins recognized RL1 monoclonal antibody. synthetically lethal both rat3-1/nup133-1 rat7-1/nup159-1 These results indicate product this nucleoporin refer as Rat2p/Nup120p.