You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
The β-Subunit of the Arabidopsis G Protein Negatively Regulates Auxin-Induced Cell Division and Affects Multiple Developmental Processes
Hemayet Ullah, Jin-Gui Chen, Brenda Temple, Douglas C. Boyes, José M. Alonso, Keith R. Davis, Joseph R. Ecker and Alan M. Jones
The Plant Cell
Vol. 15, No. 2 (Feb., 2003), pp. 393-409
Published by: American Society of Plant Biologists (ASPB)
Stable URL: http://www.jstor.org/stable/3871873
Page Count: 17
You can always find the topics here!Topics: Auxins, Cell division, Plant roots, Seedlings, Plants, Plant cells, Phenotypes, Cell growth, Hypocotyls, Proteins
Were these topics helpful?See something inaccurate? Let us know!
Select the topics that are inaccurate.
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
Plant cells respond to low concentrations of auxin by cell expansion, and at a slightly higher concentration, these cells divide. Previous work revealed that null mutants of the α-subunit of a putative heterotrimeric G protein (GPA1) have reduced cell division. Here, we show that this prototypical G protein complex acts mechanistically by controlling auxin sensitivity toward cell division. Loss-of-function G protein mutants have altered auxin-mediated cell division throughout development, especially during the auxin-induced formation of lateral and adventitious root primordia. Ectopic expression of the wild-type Gα-subunit phenocopies the Gβ mutants (auxin hypersensitivity), probably by sequestering the Gβγ-subunits, whereas overexpression of Gβ reduces auxin sensitivity and a constitutively active (Q222L) mutant Gα behaves like the wild type. These data are consistent with a model in which Gβγ acts as a negative regulator of auxin-induced cell division. Accordingly, basal repression of approximately one-third of the identified auxin-regulated genes (47 of 150 upregulated genes among 8300 quantitated) is lost in the Gβ transcript-null mutant. Included among these are genes that encode proteins proposed to control cell division in root primordia formation as well as several novel genes. These results suggest that although auxin-regulated cell division is not coupled directly by a G protein, the Gβ-subunit attenuates this auxin pathway upstream of the control of mRNA steady state levels.
The Plant Cell © 2003 American Society of Plant Biologists (ASPB)