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Enhanced AGAMOUS expression in the centre of the Arabidopsis flower causes ectopic expression over its outer expression boundaries

Spatial regulation of C-function genes controlling reproductive organ identity in the centre of the flower can be achieved by adjusting the level of their expression within the genuine central expression domain in Antirrhinum and Petunia. Loss of this control in mutants is revealed by enhanced C-gen...

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Autores principales: Cartolano, Maria, Efremova, Nadia, Kuckenberg, Markus, Raman, Smita, Schwarz-Sommer, Zsuzsanna
Formato: Texto
Lenguaje:English
Publicado: Springer-Verlag 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2729976/
https://www.ncbi.nlm.nih.gov/pubmed/19554348
http://dx.doi.org/10.1007/s00425-009-0966-7
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author Cartolano, Maria
Efremova, Nadia
Kuckenberg, Markus
Raman, Smita
Schwarz-Sommer, Zsuzsanna
author_facet Cartolano, Maria
Efremova, Nadia
Kuckenberg, Markus
Raman, Smita
Schwarz-Sommer, Zsuzsanna
author_sort Cartolano, Maria
collection PubMed
description Spatial regulation of C-function genes controlling reproductive organ identity in the centre of the flower can be achieved by adjusting the level of their expression within the genuine central expression domain in Antirrhinum and Petunia. Loss of this control in mutants is revealed by enhanced C-gene expression in the centre and by lateral expansion of the C-domain. In order to test whether the level of central C-gene expression and hence the principle of ‘regulation by tuning’ also applies to spatial regulation of the C-function gene AGAMOUS (AG) in Arabidopsis, we generated transgenic plants with enhanced central AG expression by using stem cell-specific CLAVATA3 (CLV3) regulatory sequences to drive transcription of the AG cDNA. The youngest terminal flowers on inflorescences of CLV3::AG plants displayed homeotic features in their outer whorls indicating ectopic AG expression. Dependence of the homeotic feature on the age of the plant is attributed to the known overall weakening of repressive mechanisms controlling AG. Monitoring AG with an AG-I::GUS reporter construct suggests ectopic AG expression in CLV3::AG flowers when AG in the inflorescence is still repressed, although in terminating inflorescence meristems, AG expression expands to all tissues. Supported by genetic tests, we conclude that upon enhanced central AG expression, the C-domain laterally expands necessitating tuning of the expression level of C-function genes in the wild type. The tuning mechanism in C-gene regulation in Arabidopsis is discussed as a late security switch that ensures wild-type C-domain control when other repressive mechanism starts to fade and fail.
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spelling pubmed-27299762009-08-24 Enhanced AGAMOUS expression in the centre of the Arabidopsis flower causes ectopic expression over its outer expression boundaries Cartolano, Maria Efremova, Nadia Kuckenberg, Markus Raman, Smita Schwarz-Sommer, Zsuzsanna Planta Rapid Communication Spatial regulation of C-function genes controlling reproductive organ identity in the centre of the flower can be achieved by adjusting the level of their expression within the genuine central expression domain in Antirrhinum and Petunia. Loss of this control in mutants is revealed by enhanced C-gene expression in the centre and by lateral expansion of the C-domain. In order to test whether the level of central C-gene expression and hence the principle of ‘regulation by tuning’ also applies to spatial regulation of the C-function gene AGAMOUS (AG) in Arabidopsis, we generated transgenic plants with enhanced central AG expression by using stem cell-specific CLAVATA3 (CLV3) regulatory sequences to drive transcription of the AG cDNA. The youngest terminal flowers on inflorescences of CLV3::AG plants displayed homeotic features in their outer whorls indicating ectopic AG expression. Dependence of the homeotic feature on the age of the plant is attributed to the known overall weakening of repressive mechanisms controlling AG. Monitoring AG with an AG-I::GUS reporter construct suggests ectopic AG expression in CLV3::AG flowers when AG in the inflorescence is still repressed, although in terminating inflorescence meristems, AG expression expands to all tissues. Supported by genetic tests, we conclude that upon enhanced central AG expression, the C-domain laterally expands necessitating tuning of the expression level of C-function genes in the wild type. The tuning mechanism in C-gene regulation in Arabidopsis is discussed as a late security switch that ensures wild-type C-domain control when other repressive mechanism starts to fade and fail. Springer-Verlag 2009-06-24 2009-09 /pmc/articles/PMC2729976/ /pubmed/19554348 http://dx.doi.org/10.1007/s00425-009-0966-7 Text en © The Author(s) 2009
spellingShingle Rapid Communication
Cartolano, Maria
Efremova, Nadia
Kuckenberg, Markus
Raman, Smita
Schwarz-Sommer, Zsuzsanna
Enhanced AGAMOUS expression in the centre of the Arabidopsis flower causes ectopic expression over its outer expression boundaries
title Enhanced AGAMOUS expression in the centre of the Arabidopsis flower causes ectopic expression over its outer expression boundaries
title_full Enhanced AGAMOUS expression in the centre of the Arabidopsis flower causes ectopic expression over its outer expression boundaries
title_fullStr Enhanced AGAMOUS expression in the centre of the Arabidopsis flower causes ectopic expression over its outer expression boundaries
title_full_unstemmed Enhanced AGAMOUS expression in the centre of the Arabidopsis flower causes ectopic expression over its outer expression boundaries
title_short Enhanced AGAMOUS expression in the centre of the Arabidopsis flower causes ectopic expression over its outer expression boundaries
title_sort enhanced agamous expression in the centre of the arabidopsis flower causes ectopic expression over its outer expression boundaries
topic Rapid Communication
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2729976/
https://www.ncbi.nlm.nih.gov/pubmed/19554348
http://dx.doi.org/10.1007/s00425-009-0966-7
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