A contradictory GLABRA3 allele helps define gene interactions controlling trichome development in Arabidopsis.
Previously characterized Arabidopsis gl3 mutants have trichomes that are smaller, less branched and undergo fewer rounds of endoreplication than wild-type trichomes. A new gl3 mutant, called gl3-sst, has oddly shaped trichomes that over expand during early development, undergo more endoreduplication and that have a striking nuclear morphology. The mutant nuclei consist of many interconnected lobes; however, only a single set of polytene-like chromosomes reside in the mutant nuclei. The predicted gl3-sst polypeptide has a Leu to Phe substitution (codon 78) within a region responsible for protein-protein interaction. Yeast interaction assays comparing GL3 with gl3-sst proteins show that the mutant protein interaction with GL1 and TTG1 is decreased by 75% and 50%, respectively, but there is no difference in its interaction with TRY. Furthermore, TRY has the ability to prevent the GL1 GL3 interaction and the GL1 gl3-sst interaction is even more sensitive to TRY. Analysis of plants expressing functional GFP-tagged versions of GL1, GL3 and TRY show that the proteins are localized in trichome nuclei. These results have been used to model trichome initiation in terms of protein interactions and threshold levels of activator complex.
Esch
Jeffrey J
JJ
Department of Plant Biology, University of Minnesota, St Paul, MN 55108-1095, USA.
Chen
Margaret
M
Sanders
Mark
M
Hillestad
Matthew
M
Ndkium
Sampson
S
Idelkope
Brian
B
Neizer
James
J
Marks
M David
MD
D000483:Alleles; D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018257:Helix-Loop-Helix Motifs; D010641:Phenotype; D018515:Plant Leaves / Q000254:growth & development* / Q000648:ultrastructure; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C417284:GL3 protein, Arabidopsis; C071556:GL1 protein, Arabidopsis