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Thermal down‐regulation of exportable rRNA in nuclei
Author(s) -
Wunderlich Frank,
Giese Günter,
Herlan Gerhard
Publication year - 1984
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041200215
Subject(s) - tetrahymena , biophysics , envelope (radar) , cell nucleus , chemistry , biology , microbiology and biotechnology , nucleus , telecommunications , radar , computer science
The export of rRNP particles from nuclei isolated from Tetrahymena was investigated after preincubating the nuclei at different temperatures under nonpermissive export‐conditions. We observed a new phenomenon: Temperature elevation from the sublethal cells' growth temperature, 8°C, to the optimal temperature, 28°C, lead to a gradual down‐regulation in the maximal proportion of rRNP particles subsequently exported from nuclei at 28°C. This thermal down‐regulation is apparently not due to qualitative changes in the exported rRNP particles, a derangement in the gross nuclear organization, a degradation and/or nicking of the nuclear rRNA, a gross decomposition of the major nuclear proteins, a random cross‐linking of nuclear components by disulfide bonds, or an elution of nuclear factors possibly required for rRNP export. Moreover, there is a corresponding thermal down‐regulation in nuclear envelope‐free nuclei. Our data indicate that nuclei possess a mechanism that regulates the number of potentially exportable rRNP particles at a level preceding the rRNP passage through the nuclear envelope.