Three SAC1-like genes show overlapping patterns of expression in Arabidopsis but are remarkably silent during embryo development
Article first published online: 23 APR 2003
The Plant Journal
Volume 34, Issue 3, pages 293–306, May 2003
How to Cite
Despres, B., Bouissonnié, F., Wu, H.-J., Gomord, V., Guilleminot, J., Grellet, F., Berger, F., Delseny, M. and Devic, M. (2003), Three SAC1-like genes show overlapping patterns of expression in Arabidopsis but are remarkably silent during embryo development. The Plant Journal, 34: 293–306. doi: 10.1046/j.1365-313X.2003.01720.x
- Issue published online: 23 APR 2003
- Article first published online: 23 APR 2003
- Received 8 December 2002; revised 20 January 2003; accepted 28 January 2003.
- functional homologs;
- differential expression;
- plant development
In Saccharomyces cerevisiae, the SAC1 gene encodes a polyphosphoinositide phosphatase (PPIPase) that modulates the levels of phosphoinositides, which are key regulators of a number of signal transduction processes. SAC1p has been implicated in multiple cellular functions: actin cytoskeleton organization, secretory functions, inositol metabolism, ATP transport, and multiple-drug sensitivity. Here, we describe the characterization of three genes in Arabidopsis thaliana, AtSAC1a, AtSAC1b, and AtSAC1c, encoding proteins similar to those of yeast SAC1p. We demonstrated that the three AtSAC1 proteins are functional homologs of the yeast SAC1p because they can rescue the cold-sensitive and inositol auxotroph yeast sac1-null mutant strain. The fact that Arabidopsis and yeast SAC1 genes derived from a common ancestor suggests that this plant multigenic family is involved in the phosphoinositide pathway and in a range of cellular functions similar to those in yeast. Using GFP fusion experiments, we demonstrate that the three AtSAC1 proteins are targeted to the endoplasmic reticulum. Their expression patterns are overlapping, with at least two members expressed in each organ. Remarkably, AtSAC1 genes are not expressed during seed development, and therefore additional phosphatases are required to control phosphoinositide levels in seeds.