NSP1 depletion in yeast affects nuclear pore formation and nuclear accumulation.

The essential yeast nuclear pore protein NSP1 was placed under the control of the regulatable GAL10 promoter. GAL::NSP1 cells grow normally in galactose medium, but arrest in growth upon glucose-induced repression of the GAL::nsp1 gene. During NSP1 depletion, nuclear accumulation of two reporter proteins Mat alpha 2-lacZ and PHO2-lacZ is inhibited, and the chimeric proteins appear in the cytoplasm of GAL::nsp1 cells. Furthermore, the nuclear pore density decreases within the nuclear membrane during early NSP1 depletion. Upon reinduction of the NSP1 gene after NSP1 depletion, NSP1 is targeted to the nuclear envelope, the nuclear pore density increases, and nuclear accumulation of reporter proteins is restored.