KNOX TARGET GENES · Identification and characterization of target genes regulated by KNOX transcription factors in different plant species
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2006-01-01 → 2007-12-31
- EU contribution
- €147,716
- Participants
- 1
- Scheme
- EIF
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Results in brief
Final Activity Report Summary - KNOX TARGET GENES (Identification and characterization of target genes regulated by KNOX transcription factors in different plant species)
Plant development is fundamentally different from developmental patterning in most animals in that very little of the plant body plan is established during embryogenesis. Embryogenesis in higher plants establishes a very simple structure that contains two stem cell populations - the shoot apical meristem (SAM) and the root meristem. Post-embryonic developmental patterning at these meristems is responsible for the morphology of the adult plant. Plant development and growth depends on the ability of the SAM to renew itself and at the same time differentiate the different organs. Lateral organs form on the flanks of the SAM (peripheral zone) whereas the initial cells below the apical dome constitute the rib zone and contribute to the elongation of the stem. These processes are strictly regulated and coordinated by meristematic genes, by local hormonal balance and by environmental stimuli. In plants the class 1 (KNOTTED1-like) KNOX family plays an important role in the formation and maintenance of shoot apical meristem. KNOX proteins are members of the homeodomain protein family of transcription factors that are found in all eukaryote lineages. Transcription factors are regulatory proteins that determine whether genes are transcribed or not, in other words they control when genes are switched on or off. The present project aimed to identify the genes that are regulated (target genes) by KNOX transcription factors in order to understand how KNOX factors exert their important role in plant development. Using biochemical, molecular and bioinformatic approaches, several candidates as target genes have been identified in Arabidopsis thaliana, a plant model species for genetic studies. These genes encode for proteins that are also transcription factors involved in the signal transduction of a group of steroidal plant hormones, the brassinosteroids (BRs). BRs have been shown to be involved in numerous plant processes like cell elongation and espansion, vascular differentiation and response to light, all events that are regulated by the shoot apical meristem.
Data: CORDIS, © European Union
Project objective
Animals develop all their organs entirely during embryogenesis. On the contrary, only few organs are established during plant embryogenesis. The development of all the plant organs depends on post-embryonic activity of the shoot apical meristem (SAM) and t he root meristem, which are established during embryogenesis.Plant development and growth depends on the ability of the SAM to renew itself and at the same time differentiate into various organs. These processes are strictly regulated and coordinated by meristematic genes, by local hormonal balance and by abiotic stimuli.In plants, the class 1 KNOX (KNOTTED1-like) family plays an important role in the formation and maintenance of the SAM. KNOX gene expression is first detected as the meristem is established in the embryo and disappears from cells that will give rise to leaf primordia. Over-expression of KNOX genes strongly affects cell fate.Altered cell differentiation produces dramatic changes of the whole plant architecture and leaf morphology. Mutations of some class 1 genes result in seedlings that germinate, but fail to develop any further. KNOX proteins interact with other homeodomain proteins (BELL). In animals the KNOX/BELL complex contains at least 3 subunits. In plants, KNOX and BELL proteins interact and bind the same nucleotide sequence.These findings support the hypothesis that a third interactor must provide binding-site specificity for the differential regulation of KNOX target genes. We propose a multidisciplinary project aimed at identifying KNOX primary target genes and interactors of the KNOX/BELL complex.An innovative application of Chromatin ImmunoPrecipitation (ChIP) modified for gene and protein discovery will be developed. This new approach will allow for the identification of KNOX target genes and new members of the KNOX/BELL complex.
Original text from CORDIS.
Participants
- CONSIGLIO NAZIONALE DELLE RICERCHE · ROMACoordinatorItaly
Links
Data: CORDIS, © European Union