Changes in gene expression in response to altered SHL transcript levels.
The nuclear SHL protein is composed of a N-terminal BAH domain and a C-terminal PHD finger. Both domains are found in transcriptional regulators and chromatin-modifying proteins. Arabidopsis plants over-expressing SHL showed earlier flowering and senescence phenotype. To identify SHL regulated genes, expression profiles of 35S::SHL plants were established with Affymetrix ATH1 microarrays. About 130 genes showed reduced transcript levels, and about 45 genes showed increased transcript levels in 35S::SHL plants. The up-regulated genes included AGL20 and AGL9, which most likely cause the early flowering phenotype of 35S::SHL plants. Late-flowering SHL-antisense lines showed reduced AGL20 mRNA levels, suggesting that AGL20 gene expression depends on the SHL protein. The stronger expression of senescence- and defence-related genes (such as DIN2, DIN11 and PR-1 ) is in line with the early senescence phenotype of SHL- over-expressing plants. SHL-down-regulated genes included stress response genes and the PSR3.2 gene (encoding a beta-glucosidase). SHL over-expression did not alter the tissue specificity of PSR3.2 gene expression, but resulted in reduced transcript levels in both shoots and roots. Plants with glucocorticoid-inducible SHL over-expression were established and used for expression profiling as well. A subset of genes was identified, which showed consistent changes in the inducible system and in plants with constitutive SHL over-expression.
Müssig
Carsten
C
Universität Potsdam-Genetik, c/o MPI für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Golm, Germany. muessig@mpimp-golm.mpg.de
Altmann
Thomas
T
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D015152:Blotting, Northern; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D030821:Plants, Genetically Modified; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic / Q000235:genetics*
D029681:Arabidopsis Proteins; D009687:Nuclear Proteins; D018749:RNA, Plant; C417726:SHL protein, Arabidopsis