title: Molecular cloning and characterization of a salinity stress-induced gene encoding DEAD-box helicase from the halophyte Apocynum venetum.
abstract: The genes encoding DEAD-box helicases play a key role in various abiotic stresses, including temperature, light, oxygen, and salt stress. A salt-responsive gene, designated AvDH1, was isolated from the halophyte dogbane (Apocynum venetum) by using suppression subtractive hybridization and RACE (rapid amplification of cDNA ends) PCR. The deduced amino acid sequence has nine conserved helicase motifs of the DEAD-box protein family. The AvDH1 gene is present as a single copy in the dogbane genome. This gene is expressed in response to NaCl and not polyethlene glycol (PEG) nor abscisic acid, and its expression increases with time. The transcription of AvDH1 is also induced by low temperature (4 degrees C), but its accumulation first increases then decreases with time. The purified recombinant protein contains ATP-dependent DNA helicase activity, ATP-independent RNA helicase activity, and DNA- or RNA-dependent ATPase activity. The ATPase activity of AvDH1 is stimulated more by single-stranded DNA than by double-stranded DNA or RNA. These results suggested that AvDH1 belonging to the DEAD-box helicase family is induced by salinity, functions as a typical helicase to unwind DNA and RNA, and may play an important role in salinity tolerance.
authors.affiliation: State Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Taian, Shandong 271018, PR China.
authors.forename: H H
authors.initials: HH
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: S L
authors.initials: SL
authors.lastname: Fan
authors.forename: M Z
authors.initials: MZ
authors.lastname: Song
authors.forename: X L
authors.initials: XL
authors.lastname: Han
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.forename: F F
authors.initials: FF
authors.lastname: Shen
mesh_terms: D000222:Adaptation, Physiological; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000595:Amino Acid Sequence; D030010:Apocynum / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004265:DNA Helicases / Q000378:metabolism; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D012965:Sodium Chloride; D000251:Adenosine Triphosphatases; D004265:DNA Helicases; D053487:DEAD-box RNA Helicases