The Purification,Glycosylation Structure And Properties Of Hen Egg White Ovomacroglubulin

Photomorphogenisis is a plant developmental process in response to environmental light stimulation.Grown underground in soil,root is shaded from illumination.The convenient Petri dish methodology for growing Arabidopsis in the laboratory was developed over half a century,exposes root to light unexpectedly.Currently,researches on photomorphogenisis concentrate on aboveground phenotypes,however,how roots response to light in this process is still largely unknown.Elongated hypocotyl 5(HY5)is one of the most important key regulators in photomorphogenisis.HY5 homolog(HYH),is the closest homolog of HY5 in the Arabidopsis genome.Through the research on in vivo interaction mechanism of HY5-HYH in Arabidopsis,this study thus expects to examine the root traits in photomorphogenisis and uncover the local expression changes of specific genes.we found that auxin distribution marker DR5::GUS had increased accumulated maximum in cotyledon,primary root and lateral root of hy5 mutant.hy5 affects polar auxin transport through PIN1/PIN2 carriers and induces enhanced auxin accumulation in root.We construct HY5 and HYH reporter lines of both promoter and protein fusion GUS or GFP reporter gene.Through them,we observed that although largely identical in aboveground,HY5 and HYH had distinct expression patterns in root.HY5 other than HYH involved in every stages of lateral development ever since initiation to elongation.Decapitation experiment suggested that HY5 and HYH response to light was root autonomous.HY5 specifically transcriptional activates HYH expression in root without affecting aboveground.HYH has 4 splicing variants in vivo,and they could partially rescue hy5 lateral root phenotypes.Although there is gene redundancy,hy5 not hyh is the master factor in mutant phenotypes.Transparent dishes method was modified to allow roots to be kept in darkness.Root architecture is enhanced and expanded in hy5-like shape in this situation.The Arabidopsis hypocotyl is a useful model for investigating cell elongation.Light inhibits hypocotyl elongation in HY5 mediated pathway.High temperature promotes hypocotyl elongation.Hypocotyl elongation in hy5 mutant is much more pronounced which indicates that HY5 functions as a repressor in high temperature induced hypocotyl elongation.Both auxin transport inhibitor and GA biosynthesis inhibitor could strongly reduced the elongation response to temperature of hy5 mutant.GA2oxs belong to a class of genes encode GA deactivation enzymes,which are putative HY5 binding targets.The results from GUS fusion reporter lines evidence that in vivo activation of GA2oxs is dependent on HY5.Overexpression of GA2oxs could repress hypocotyl elongation and temperature responses of hy5 mutant.We generated an EMS-mutagenized Arabidopsis population in the hy5 mutant background and performed a screen to identify mutants with altered hypocotyl and/or root phenotypes.Further analysis and characterization of these mutants are currently ongoing.