Project description:We performed a chromatin immunoprecipitation-based microarray experiment (ChIP chip) in order to identify GTL1 and DF1 direct target genes
Project description:How plants determine the final size of growing cells is an important, yet unanswered question. Root hairs provide an excellent model system to study this question since their final cell size is remarkably constant under given environmental conditions. In this study we demonstrate that a trihelix transcription factor GT-2-LIKE1 (GTL1) and its homolog DF1 repress root hair growth in Arabidopsis. Our transcriptional data, combined with genome-wide chromatin binding data, show that GTL1 and DF1 directly bind the RSL4 promoter and regulate its expression to repress root hair growth. Our data further show that GTL1 and RSL4 regulate each other as well as a set of common downstream genes, many of which have previously been implicated in root hair growth. This study therefore uncovers a core regulatory module that fine-tunes the extent of root hair growth by orchestrated actions of opposing transcription factors.
Project description:To understand how GTL1 regulates cell growth, we first identified its potential direct targets by the chromatin immunoprecipitation followed by the hybridization on an Affymetrix Arabidopsis Tiling 1.0R array (ChIP-chip). To enrich the genomic region bound by GTL1 in vivo, we harvested whole aerial parts of 12-day-old gtl1-1 plants complemented with the pGTL:GTL1:GFP constructs and immunoprecipitated the chromatin fragments associated with GTL1-GFP proteins using antibodies against GFP. After applying a cut-off P-values of 0.001of MAT (Model-based analysis of tiling array), we identified a total number of 3,900 putative immediate target genes that showed consistent binding by GTL1.
Project description:To understand how GTL1 regulates cell growth, we first identified its potential direct targets by the chromatin immunoprecipitation followed by the hybridization on an Affymetrix Arabidopsis Tiling 1.0R array (ChIP-chip). To enrich the genomic region bound by GTL1 in vivo, we harvested whole aerial parts of 12-day-old gtl1-1 plants complemented with the pGTL:GTL1:GFP constructs and immunoprecipitated the chromatin fragments associated with GTL1-GFP proteins using antibodies against GFP. After applying a cut-off P-values of 0.001of MAT (Model-based analysis of tiling array), we identified a total number of 3,900 putative immediate target genes that showed consistent binding by GTL1. Two IP chips compared to two Input chips.
Project description:GT2-LIKE 1 (GTL1) is a negative regulator of stomatal development and its repressed expression under water deficit can result in enhanced drought tolerance. As a transcription factor, GTL1 has been implicated in diverse developmental roles. We hypothesized that GTL1 represses multiple drought tolerance pathways, leading to the drought tolerance phenotype of the gtl1-4 knockout mutant. RNA-Seq data indicates that GTL1 regulates genes involved in ribosome biogenesis in emerging leaves and secondary metabolite synthesis in expanding leaves.
Project description:Total RNA from trichomes of fifth and sixth rosette leaves of three-week-old wild-type and gtl1-1 mutants (Figure 3B) were extracted. We found a total number of 1,759 genes, corresponding to 1,694 probes on the ATH1 chip, that show differential expression of at least 1.3-fold. Out of these 1,694 genes, 47.2% are positively regulated and 52.8% are negatively regulated by GTL1. Compared gene expressions in fifth and sixth rosette leaves of three-week-old wild-type and gtl1-1 mutants