DISRUPTION OF THE NUCLEOPORIN GENE NUP133 RESULTS IN CLUSTERING OF NUCLEAR-PORE COMPLEXES

We have characterized a protein with an estimated molecular mass of 13 0 kDa that is contained in a highly enriched yeast nuclear pore comple x (NPC) fraction, Partial amino acid sequence from this protein has le d us to a previously identified open reading frame on chromosome XI of Saccharomyces cerevisiae encoding a protein of 133 kDa. Due to its co enrichment with NPCs during cell fractionation and the phenotype obser ved in the disrupted strain, we propose to term the gene encoding this protein NUP133, Cells carrying a disrupted copy of NUP133 were temper ature sensitive for growth, In addition, abnormal clustering of NPCs w as observed. This phenotype is similar to that previously observed in the disruption of another nucleoporin gene, NUP145. We speculate that the gene product of NUP133, Nup133p, may functionally overlap with the NUP145 gene product, Nup145p, and that these proteins may be involved in maintaining the position of the NPC within the nuclear envelope.