Posttranscriptional control in the expression of the genes coding for high-light-regulated HL#2 proteins
An antibody was raised against the protein HL#2 which is a nuclear-encoded light-stress-induced protein of barley (Hordeum vulgare L.). The expression of the mRNA and the protein of HL#2 was determined under the influence of high light and methyl jasmonate. The mRNA of HL#2 was induced by high light (1800 &mgr;mol m(-2) s(-1) and 25 degrees C) and the steady-state levels remained elevated for up to 48 h of exposure to high-light stress. In contrast, using an antibody against HL#2 there was no observable change in the level of HL#2 proteins of 18 kDa and 15.5 kDa during the same treatment. These data indicate a pronounced stress-induced control of HL#2 expression at a post-transcriptional level. In the presence of methyl jasmonate (45 &mgr;M), the induction of HL#2 occurred together with that of the two most closely related jasmonate-inducible proteins (JIPs) of 32.6 and 32.7 kDa, as judged by their cross-reactivity with the antibody against HL#2. In contrast to the mRNA and protein levels of early light-inducible proteins (ELIPs) in green barley, those of HL#2 appeared not to be influenced by low temperatures. Therefore, the control of ELIPs and HL#2 by high light fluxes may be measured via the same photoreceptor but must, at least partially, be under the control of two divergent signal transduction chains.
Menhaj
AR
Institut fur Botanik, Universitat Hannover, Herrenhauser Strasse 2, D-30419 Hannover, Germany.
Mishra
SK
Bezhani
S
Kloppstech
K