Showing papers by "Natasha V. Raikhel published in 2006"
TL;DR: Results indicate that RGP1 and RGP2 are required during microspore development and pollen mitosis, either affecting cell division and/or vacuolar integrity and taken together indicate that the double mutant is lethal and demonstrates the critical role of RGPs, particularly in pollen development.
Abstract: Reversibly glycosylated polypeptides (RGPs) have been implicated in polysaccharide biosynthesis. To date, to our knowledge, no direct evidence exists for the involvement of RGPs in a particular biochemical process. The Arabidopsis (Arabidopsis thaliana) genome contains five RGP genes out of which RGP1 and RGP2 share the highest sequence identity. We characterized the native expression pattern of Arabidopsis RGP1 and RGP2 and used reverse genetics to investigate their respective functions. Although both genes are ubiquitously expressed, the highest levels are observed in actively growing tissues and in mature pollen, in particular. RGPs showed cytoplasmic and transient association with Golgi. In addition, both proteins colocalized in the same compartments and coimmunoprecipitated from plant cell extracts. Single-gene disruptions did not show any obvious morphological defects under greenhouse conditions, whereas the double-insertion mutant could not be recovered. We present evidence that the double mutant is lethal and demonstrate the critical role of RGPs, particularly in pollen development. Detailed analysis demonstrated that mutant pollen development is associated with abnormally enlarged vacuoles and a poorly defined inner cell wall layer, which consequently results in disintegration of the pollen structure during pollen mitosis I. Taken together, our results indicate that RGP1 and RGP2 are required during microspore development and pollen mitosis, either affecting cell division and/or vacuolar integrity.
111 citations
TL;DR: A brief accounting of Dr. Martin Gibbs' professional career is offered in celebration of his professional career as chief editors of Plant Physiology.
Abstract: Dr. Martin Gibbs died at his home on July 24, 2006, in Lexington, MA, at the age of 83. We three succeed Marty as chief editors of Plant Physiology , a position he held from 1963 to 1992. We offer this brief accounting in celebration of his professional career.
In the fall of 1940, Marty began his