Tesis doctoral de Francisco Scaglia Linhares
Plants have evolved adaptative responses that allow them to grow under conditions of limited phosphate (pi) supply. These responses involve physiological and developmental changes, and are controlled by a complex regulatory mechanism whose details are beguinning to be understood. Phr1 transcription factor is a key component of this regulatory system, previously described by rubio et al., (2001) phr1 mutants display impaired pi starvation induced physiological and developmental responses. In addition, phr1 is known to bind in vitro to the sequence gnatatnc called p1bs.%&/In this study, we investigated the transcriptome fluctuations due to pi starvation and the control of phr1 on these transcriptional changes using oligo-based microarrays. The publicavailability of microarray data, through the genevestigator database, enabled us to compare the pi starvation response with other treatments, highlighting correlations between pi starvation and other treatments. Phr1 regulated genes display similar behaviour (with regard to co-modulation by other signals) than all other pi starvation responsive genes. This indicates that phr1 controls both pi starvation specific and general stress responsive genes.%&/The in vivo analysisof the cis-regulatory element p1bs demonstrated its important role in pi starvation responsiveness, and demonstrated that the precise localizationof p1bs in the promoter greatly affects its functionality. We also constructed ana artificial phr1 responsive element that showed correct in vivo functionality, and therefore it coulfd be used as a sensor for pi starvation.%&/Finally, we also performed analysis of epigenetic modifications in the promoter region of some pi starvation responsive genes. The results revealed that histone modifications establish a new layer of differential transcriptional regulation in the control of pi starvation inducible genes. We also encountered in arabidopsis a histone eviction mechanism in the p1bs proximal region of the promoterof the acid phosphatase acp5, even displaying no sequence homology to the yeast phosphatases pho5 and pho8, converged to a common chromatin remodelling mechanism. Nucleosome remodelling mechanism has been previously described for the promoter of the yeast genes for pho5 and pho8 phosphateses.
Datos académicos de la tesis doctoral «Regulación transcripcional de la respuesta al ayuno de fosfato en arabidopsis thaliana«
- Título de la tesis: Regulación transcripcional de la respuesta al ayuno de fosfato en arabidopsis thaliana
- Autor: Francisco Scaglia Linhares
- Universidad: Autónoma de Madrid
- Fecha de lectura de la tesis: 17/11/2008
Dirección y tribunal
- Director de la tesis
- Paz Ares Rodriguez Francisco Javier
- Tribunal
- Presidente del tribunal: sonsoles Campuzano corrales
- sabrina Sabatini (vocal)
- Antonio Leyva tejada (vocal)
- pablo Vera vera (vocal)