Russo, Laura A. , Verhoeven, Elizabeth C. , Barton, M. Kathryn , Jenik, Pablo D. .
A mutation in subunit RPN5a of the regulatory particle of the proteasome affects cell division along the shoot-root axis during Arabidopsis embryogenesis.
The mechanisms by which plants control cell numbers in particular organs are not well understood. During Arabidopsis embryogenesis there is a tight regulation of the number of cells along the two axes of the embryo (shoot-root and radial). We have isolated several mutants that seem to affect primarily the growth of the shoot-root axis after the globular stage. Embryos mutant for one of these loci, MARIPOSA, develop normally until the late globular stage. After the transition to heart stage there are no or very few cell divisions in the prospective hypocotyl and embryonic root. However, cell divisions continue in the cotyledon primordia. Analysis of the morphology and several reporter genes suggest that the embryo is properly patterned. Most mariposa embryos are viable, and grow into very small, sterile plants. The leaves of these plants appear to have fewer cells than wild type leaves. We present a description of the embryonic and some of the post-embryonic phenotypes, and evidence that mariposa is a mutation in subunit RPN5a of the regulatory particle of the proteasome. Our results imply that proteasome-regulated processes are important for the proper control of cell number in Arabidopsis.
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1 - Carnegie Institution, Department of Plant Biology, Stanford, CA, 94305
2 - Oberlin College, Department of Biology, Oberlin, OH, 44074
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM