Comparative expression and transcript initiation of three peach dehydrin genes.
Dehydrin genes encode proteins with demonstrated cryoprotective and antifreeze activity, and they respond to a variety of abiotic stress conditions that have dehydration as a common component. Two dehydrins from peach (Prunus persica L. [Batsch.]) have been previously characterized; here, we describe the characterization of a third dehydrin from peach bark, PpDhn3, isolated by its response to low temperature. The expression of all three dehydrin genes was profiled by semi-quantitative reverse transcription PCR, and transcript initiation was mapped for all three genes using the RNA ligase-mediated 5' rapid amplification of cDNA ends technique. PpDhn3 transcripts from bark collected in December or July, as well as transcripts from developing fruit, initiated at a single site. Although most of the PpDhn1 transcripts initiated at a similar position, those from young fruit initiated much further upstream of the consensus TATA box. Bark and fruit transcripts encoding PpDhn2 initiated ca. 30 bases downstream of a consensus TATA box; however, transcripts from ripe fruit initiated further upstream. Ripe fruit transcripts of PpDhn2 contain a 5' leader intron which is predicted to add some 34 amino acids to the N-terminal methionine of the cognate protein when properly processed. Secondary structure prediction of sequences surrounding the TATA box suggests that conformational transitions associated with decreasing temperature contribute to the regulation of expression of the cold-responsive dehydrin genes. Taken together these results reveal new, unexpected levels of gene regulation contributing to the overall expression pattern of peach dehydrins.
Bassett
Carole Leavel
CL
USDA, ARS, Appalachian Fruit Research Station, 2217 Wiltshire Road, Kearneysville, WV 25430, USA. carole.bassett@ars.usda.gov
Wisniewski
Michael E
ME
Artlip
Timothy S
TS
Richart
Greg
G
Norelli
John L
JL
Farrell
Robert E
RE
D016000:Cluster Analysis; D003080:Cold Temperature; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D005638:Fruit / Q000235:genetics* / Q000254:growth & development; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D024301:Plant Bark / Q000235:genetics; D010940:Plant Proteins / Q000145:classification / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D020033:Protein Isoforms / Q000145:classification / Q000235:genetics; D027861:Prunus / Q000235:genetics* / Q000254:growth & development; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D017422:Sequence Analysis, DNA; D016385:TATA Box / Q000235:genetics; D013696:Temperature; D024363:Transcription Initiation Site
D018744:DNA, Plant; D010940:Plant Proteins; D020033:Protein Isoforms; C070556:dehydrin proteins, plant