The Arabidopsis AtDi19 gene family encodes a novel type of Cys2/His2 zinc-finger protein implicated in ABA-independent dehydration, high-salinity stress and light signaling pathways.
The AtDi19 (drought-induced) gene family encodes seven hydrophilic proteins that contain two atypical Cys2/His2 (C2H2) zinc finger-like domains that are evolutionarily well-conserved within angiosperms suggesting a conserved and important function. Five of the seven Arabidopsis AtDi19-related:DsRed2 fusion proteins exhibited speckled patterns of localization within the nucleus as shown by transient expression analysis in Arabidopsis protoplasts. In contrast, AtDi19-2:DsRed2 was present in the nucleus and cytoplasm, whereas AtDi19-4:DsRed2 was localized to the nuclear periphery. mRNA expression studies showed that AtDi19 genes are ubiquitously expressed in Arabidopsis tissues, although some differences were observed. In seedlings, RT-PCR analyses showed that AtDi19-1 and AtDi19-3 steady-state transcript amounts were rapidly induced by dehydration, whereas transcript amounts for AtDi19-2 and AtDi19-4 increased in response to high-salt stress. In addition, the mRNA abundance of all the AtDi19-related gene family members was not regulated by ABA. These data, taken together, suggest that several AtDi19-related gene family members may function in ABA-independent, dehydration and salinity stress signaling pathways. However, they may also be regulated by other abiotic stimuli. AtDi19-7, for example, has been implicated in regulating light signaling and responses. Finally, we show that most AtDi19-related proteins are phosphorylated in vitro by calcium-dependent protein kinases suggesting that this post-translational modification may be important for regulating the function of this novel protein family.
Milla
Miguel A Rodriguez
MA
Department of Biochemistry and Molecular Biology, University of Nevada, Reno, 89557-0014, USA.
Townsend
Jared
J
Chang
Ing-Feng
IF
Cushman
John C
JC
D000040:Abscisic Acid / Q000378:metabolism; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D017124:Conserved Sequence; D003681:Dehydration; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant; D008027:Light; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000502:physiology; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011523:Protoplasts / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction; D012965:Sodium Chloride / Q000378:metabolism; D016335:Zinc Fingers
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; C508910:Di19 protein, Arabidopsis; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012965:Sodium Chloride; D000040:Abscisic Acid