Analysis of tissue-specific expression of Arabidopsis thaliana HSP90-family gene HSP81.
We have isolated three HSP90-family genes from Arabidopsis: HSP81-1 which is heat-inducible, and HSP81-2 and -3 which are highly expressed under normal growth temperatures. Northern blot analysis and RNase protection analysis, using gene specific probes, showed that HSP81-2 and -3 mRNA were present in all tissues and abundant in roots, floral bud clusters, and flowers at 22 degrees C. A small amount of HSP81-1 mRNA was detected only in roots. In situ hybridization and histochemical analysis using transgenic plants carrying chimeric gene fusions, with an HSP81 promoter region fused to a beta-glucuronidase (GUS) gene, confirmed these results. At 22 degrees C, high GUS activity was observed in the root apical meristems, pollen and tapeta in HSP81-2::GUS and HSP81-3::GUS transgenic plants, while only branches of the root in HSP81-1::GUS transgenic plants expressed high GUS activity. After 2 hours of 35 degrees C treatment, extensively high GUS activity was observed in all tissues in HSP81-1::GUS transgenic plants, while elevated but tissue specific expression was observed in HSP81-2 and -3 transgenic plants. Exogenous application of various chemicals such as ABA, GA3, kinetin, IAA, NaCl, and mannitol revealed that 10 mM IAA and 0.1 M NaCl significantly enhanced the accumulation of HSP81-2 and -3 transcripts. Only a slight response to IAA was observed in HSP81-1 mRNA accumulation at 22 degrees C; the increase was possibly caused by a novel pathway other than heat-shock-response pathway.
Yabe
N
N
Molecular Genetics Research Laboratory, University of Tokyo, Japan.
Takahashi
T
T
Komeda
Y
Y
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D015698:Genomic Library; D005966:Glucuronidase / Q000096:biosynthesis / Q000235:genetics; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics*; D006651:Histocytochemistry; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014018:Tissue Distribution
D029681:Arabidopsis Proteins; C092856:HSP81-3 protein, Arabidopsis; D018841:HSP90 Heat-Shock Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D005966:Glucuronidase