NSP1, a yeast protein located at the nuclear periphery, is required for the cell cycle of Saccharomyces cerevisiae

Proteins located at the nuclear periphery and required for nuclear and cell division are not known in yeast. We recently identified a novel nucleoskeletal-like protein in Saccharomyces cerevisiae, which is in close proximity to the spindle pole body and the nuclear membrane. NSP1 has an essential function, since haploid yeast cells with a defective NSP1 gene cannot grow. In this report, we demonstrate that yeast cells which carry the NSP1 gene under the regulatory GAL10 promoter exhibit abnormal cell morphology both under conditions where the level of NSP1 expression is greatly increased (the GAL10 promoter is induced) or limited (the GAL10 promoter is not induced). This result suggests that NSP1 is required for the coordinated cell cycle in S. cerevisiae.