Cold‐ and salinity stress‐induced bipolar pea DNA helicase 47 is involved in protein synthesis and stimulated by phosphorylation with protein kinase C

Abstract

SummaryHelicases are involved in the metabolism of nucleic acid; this is very sensitive to the abiotic stresses that reduce plant growth and productivity. However, the molecular targets responsible for this sensitivity have not been well studied. Here we report on the isolation and characterization of cold-and salinity stress-induced pea DNA helicase 47 (PDH47). The transcript of PDH47 was induced in both shoots and roots under cold (4°C) and salinity (300 mM NaCl) stress, but there was no change in response to drought stress. Tissue-specific differential regulation was observed under heat (37°C) stress. ABA treatment did not alter expression of PDH47 in shoots but induced its mRNA in roots, indicating a role for PDH47 in both the ABA-independent and ABA-dependent pathways in abiotic stress. The purified recombinant protein (47 kDa) contains ATP-dependent DNA and RNA helicase and DNA-dependent ATPase activities. With the help of photoaffinity labeling, PDH47 was labeled by [a-32 P]-ATP. PDH47 is a unique bipolar helicase that contains both 3¢ to 5¢ and 5¢ to 3¢ directional helicase activities. Anti-PDH47 antibodies immunodeplete the activities of PDH47 and inhibit in vitro translation of protein. Furthermore, the PDH47 protein showed upregulation of protein synthesis. The activities of PDH47 are stimulated after phosphorylation by protein kinase C at Ser and Thr residues. Western blot analysis and in vivo immunostaining, followed by confocal microscopy, showed PDH47 to be localized in both the nucleus and cytosol. The discovery of cold-and salinity stress-induced DNA helicase should make an important contribution to a better understanding of DNA metabolism and stress signaling in plants. Its bipolar helicase activities may also be involved in distinct cellular processes in stressed conditions.

Characterization of transcription factor gene SNAC2 conferring cold and salt tolerance in rice

“…Actually, homologous genes of many up-regulated genes have been documented with functions in the responses or adaptations to abiotic stresses in plants. The products of these genes include peroxidase (Murgia et al 2004), ornithine aminotransferase (Roosens et al 1998), lysine ketoglutarate reductase (Galili et al 2001), heavy metal-associated protein (Barth et al 2004), sodium/hydrogen exchanger (Shi et al 2003), heat shock protein (Sun et al 2001), GDSLlike lipase (Naranjo et al 2006), BURP domain (RD22) containing protein (Goh et al 2003), and phenylalanine ammonia lyase (Vincent et al 2005), ATP-dependent helicase (Vashisht et al 2005), Tat pathway signal sequence family protein (Ochsner et al 2002). Plant growth is often suppressed under stress conditions.…”

An Insecticidal GroEL Protein with Chitin Binding Activity from Xenorhabdus nematophila

“…Biochemical Characterization of XnGroEL-ATPase activity and in vitro porcine lactate dehydrogenase refolding assay was performed as described previously (17,18).…”

Genetic and Molecular Aspects of Plant Response to Drought in Annual Crop Species

“…Two DEAD-box-related helicases, DNA Helicase 47 (PDH47) and PDH45 are induced by a variety of abiotic stresses in pea (Chinnusamy et al, 2004;Sanan-Mishra et al, 2005;Vashisht et al, 2005). The expression of PDH47 in particular is regulated in a tissue specific manner: the gene is induced by cold and salinity stress in shoots and roots, and by heat and ABA treatment only in roots (Chinnusamy et al, 2004).…”