Cold-shock regulation of the Arabidopsis TCH genes and the effects of modulating intracellular calcium levels.

Abstract

The Arabidopsis TCH genes, which encode calmodulin-related proteins and a xyloglucan endotransglycosylase, are shown to be up-regulated in expression following cold shock. We investigated a possible role of fluctuations in intracellular calcium ion concentrations ([Ca2+]) in the cold-shock-induced TCH gene expression. Transgenic plants harboring the apoaequorin gene were generated to monitor [Ca2+]) and to test the necessity of cold-induced [Ca2+] increases for TCH expression. Cold-shock-induced [Ca2+] increases can be blocked by La3+ and Gd3+, putative plasma membrane Ca2+ channel blockers, and 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, an extracellular Ca2+ chelator. Cold-shock-induced expression of the TCH genes is inhibited by levels of La3+, Gd3+, and 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, that have been shown to block [Ca2+] increases. These data support the hypotheses that (a) intracellular [Ca2+] increases following cold shock require extracellular Ca2+ and may derive from a Ca2+ influx mediated by plasmalemma Ca2+ channels, and (b) cold up-regulation of expression of at least a subset of the TCH genes requires an intracellular [Ca2+] increase. The inhibitors are also shown to have stimulus-independent effects on gene expression, providing strong evidence that these commonly used chemicals have more complex effects than generally reported.

• Authors: D H Polisensky, J Braam
• Journal: Plant physiology (Plant Physiol) Vol. 111 Issue 4 Pg. 1271-9 (Aug 1996) ISSN: 0032-0889 [Print] United States
• PMID: 8756505 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Calcium Channel Blockers
• Calmodulin
• Chelating Agents
• Plant Proteins
• Glycosyltransferases
• xyloglucan endotransglycosylase
• Calcium

Topics

• Arabidopsis (genetics)
• Calcium (metabolism)
• Calcium Channel Blockers (pharmacology)
• Calmodulin (metabolism)
• Chelating Agents (pharmacology)
• Cold Temperature
• Gene Expression Regulation, Plant (drug effects)
• Glycosyltransferases (genetics)
• Plant Proteins (genetics)