|Liu, Hong - PLANT BIOLOGY UOFI URBANA|
Submitted to: Plant Physiology Supplement
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 1998
Publication Date: N/A
Technical Abstract: Earlier work has shown that in chilling sensitive plants low temperature can induce a delay of the circadian timing of gene expression. We have examined protein profiles following pulse labeling with radiolabeled methionine comparing plants that had been chilled for 16 h at 14 deg C to controls that had been maintained at room temperature in the dark for 16 h. Several, seemingly novel proteins are changed by the chilling treatment including one rapidly turning over, heavily-labeled polypeptide that runs at 35kDa on SDS-PAGE. The normal diurnal expression pattern of this tomato leaf protein reveals that is actively synthesized in the late afternoon. We have isolated, microsequenced the protein p35 and get about 10 amino acid of two internal sequences. Based on one of the amino acid sequences, we have cloned the partial cDNA of p35 gene in tomato by using asymmetric PCR. The 890bp sequence shows no homology with any known gene. The Northern blot hybridized with the probe made this clone shows that the expression of p35 gene has a diurnal rhythm with a high expression in the late afternoon. RNA level of p35 gene also shows a strong circadian rhythm in constant darkness for three days. Chilling delays the gene expression of p35 transcript whether chilling exposure starts at the lowest or highest point in circadian expression pattern. We are now trying to clone the full length sequence of this gene and identify its function.