Poster: Cell walls
Abs #
619: The XTHs of Arabidopsis: Function and Expression Regulation
The plant cell wall is a complex structure composed in part of cellulose microfibrils interconnected by a network of hemicellulose. The most abundant hemicellulose of dicotyledonous plants is xyloglucan. Xyloglucan endotransglucosylase/hydrolases (XTHs) cleave xyloglucan polymers and religate the newly generated reducing ends to other xyloglucan polymers (Rose et al., 2002). Although the biochemical activity of this enzyme is well defined, the physiological consequences of XTH activity in vivo remain undetermined. XTH biochemical activity, however, predicts a role in modification of the cell wall.
Analysis of the Arabidopsis database reveals an extensive gene family that encodes thirty-three XTH proteins. These proteins are highly similar and share a conserved motif that is predicted to be necessary for their activity, as well as N-linked glycosylation sites and putative signal sequences for translation at ER membranes
My research centers on investigating the physiological functions of XTHs in vivo as well as shedding light on the reasons for Arabidopsis to have this large gene family. Using a reverse genetics screen, I have identified 27 mutations in 22 genes. I have chosen to focus primarily on two mutants, xth15-1 and xth12-1, for phenotypic characterization and further study. To study the regulation of XTH gene expression, I generated reporter gene fusions using ß-glucuronidase (GUS) and have begun to analyze GUS expression in transgenic plants. The data suggests unique functions and expression patterns for the Arabidopsis XTHs.
This research is supported by the NSF (IBN0313432 and IBN9982654).
