z-logo
open-access-imgOpen Access
tRNA transport from the nucleus in a eukaryotic cell: carrier-mediated translocation process.
Author(s) -
Michael Zasloff
Publication year - 1983
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.80.21.6436
Subject(s) - transfer rna , nuclear pore , xenopus , nuclear transport , microbiology and biotechnology , nucleus , cell nucleus , biology , biophysics , cytoplasm , microinjection , t arm , rna , biochemistry , gene
The mechanism by which a tRNA molecule is delivered from the nucleus of a cell to the cytoplasm has been studied in the Xenopus laevis oocyte utilizing nuclear microinjection and manual microdissection techniques. tRNA nuclear transport in this cell resembles a carrier-mediated translocation process rather than diffusion through a simple pore or channel. tRNA transport is saturable by tRNA, with a maximal rate measured to be about 190 X 10(7) molecules per min per nucleus (21 degrees C) in the mature oocyte. Competitive inhibition between two different tRNA species can be demonstrated, suggesting that many tRNA species share a common carrier system. tRNA nuclear transport is sharply dependent on temperature, with an optimal rate observed at 31 degrees C. A single G-to-U substitution at position 57 in the vertebrate tRNAMeti molecule reduces the transport rate of this tRNA by a factor of about 20, implicating this highly conserved region of the tRNA molecule (loop IV) as critical for recognition by the transport mechanism. On morphologic grounds I propose that ribosome-like components surrounding the nuclear pore may function as the tRNA translocation "motor." The tRNA nuclear transport mechanism represents a distinctly eukaryotic process and a site of potential control over cell growth and proliferation.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.
Having issues? You can contact us here