A 40 kDa nuclear membrane protein changes its concentration and localization within the nuclear envelope of the yeast Saccharomyces cerevisiae in a cell-cycle dependent manner.
In order to identify and characterize structural components in the nuclear membrane of Saccharomyces cerevisiae which show a cell-cycle dependent regulation, we have undertaken a combined biochemical/immunofluorescence microscopy approach. Antisera raised against nuclear membrane proteins from yeast lead to the identification of a 40 kDa membrane protein which cofractionated with nuclei upon cell fractionation. This 40 kDa membrane protein partitioned into the Triton X-114 phase and was not extracted from purified nuclei at alkaline pH. Using affinity-purified antibodies against this protein, the antigen was localized at the nuclear periphery suggesting that it is an integral constituent of the nuclear envelope. However, the 40 kDa antigen revealed a heterogenous distribution within the nuclear membrane: in indirect immunofluorescence microscopy, nuclei isolated from an asynchronously growing yeast culture showed either no immunodetectable antigen or contained it in a cap-, dot- or ring-like conformation. Using synchronized yeast cultures, we could demonstrate cell-cycle dependent changes of concentration and localization of the 40 kDa protein within the nuclear envelope.
Schimmang
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European Molecular Biology Laboratory, Heidelberg/Federal Republic of Germany.
Hurt
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EC
D002453:Cell Cycle; D002458:Cell Fractionation; D019084:Fluorescent Antibody Technique, Indirect; D016193:G1 Phase; D015151:Immunoblotting; D008565:Membrane Proteins / Q000032:analysis* / Q000276:immunology; D008856:Microscopy, Fluorescence; D008970:Molecular Weight; D009154:Mutation; D009685:Nuclear Envelope / Q000737:chemistry*; D009687:Nuclear Proteins / Q000032:analysis / Q000276:immunology; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000166:cytology* / Q000235:genetics / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis* / Q000276:immunology
D008565:Membrane Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins