The plant hormone auxin is a fundamental regulator of organ patterning and development that regulates gene expression via the canonical AUXIN RESPONSE FACTOR (ARF) and AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) combinatorial system. ARF and Aux/IAA factors interact, but at high auxin concentrations, the Aux/IAA transcriptional repressor is degraded, allowing ARF-containing complexes to activate gene expression. ARF5/MONOPTEROS (MP) is an important integrator of auxin signaling in Arabidopsis development and activates gene transcription in cells with elevated auxin levels. Here, we show that in ovules, MP is expressed in cells with low levels of auxin and can activate the expression of direct target genes. We identified and characterized a splice variant of MP that encodes a biologically functional isoform that lacks the Aux/IAA interaction domain. This MP11ir isoform was able to complement inflorescence, floral, and ovule developmental defects in mp mutants, suggesting that it was fully functional. Our findings describe a novel scenario in which ARF post-transcriptional regulation controls the formation of an isoform that can function as a transcriptional activator in regions of subthreshold auxin concentration.

Alternative Splicing Generates a MONOPTEROS Isoform Required for Ovule Development / M. Cucinotta, A. Cavalleri, A. Guazzotti, C. Astori, S. Manrique, A. Bombarely, S. Oliveto, S. Biffo, D. Weijers, M.M. Kater, L. Colombo. - In: CURRENT BIOLOGY. - ISSN 0960-9822. - (2020). [Epub ahead of print]

Alternative Splicing Generates a MONOPTEROS Isoform Required for Ovule Development

M. Cucinotta
Primo
;
A. Cavalleri
Secondo
;
A. Guazzotti;S. Manrique;A. Bombarely;S. Oliveto;S. Biffo;M.M. Kater
Penultimo
;
L. Colombo
Ultimo
2021

Abstract

The plant hormone auxin is a fundamental regulator of organ patterning and development that regulates gene expression via the canonical AUXIN RESPONSE FACTOR (ARF) and AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) combinatorial system. ARF and Aux/IAA factors interact, but at high auxin concentrations, the Aux/IAA transcriptional repressor is degraded, allowing ARF-containing complexes to activate gene expression. ARF5/MONOPTEROS (MP) is an important integrator of auxin signaling in Arabidopsis development and activates gene transcription in cells with elevated auxin levels. Here, we show that in ovules, MP is expressed in cells with low levels of auxin and can activate the expression of direct target genes. We identified and characterized a splice variant of MP that encodes a biologically functional isoform that lacks the Aux/IAA interaction domain. This MP11ir isoform was able to complement inflorescence, floral, and ovule developmental defects in mp mutants, suggesting that it was fully functional. Our findings describe a novel scenario in which ARF post-transcriptional regulation controls the formation of an isoform that can function as a transcriptional activator in regions of subthreshold auxin concentration.
alternative splicing; arabidopsis; arf5; auxin; auxin signalling; auxin-responce factor; monopteros; ovule; ovule development; plant development
Settore BIO/01 - Botanica Generale
Settore BIO/11 - Biologia Molecolare
3-dic-2020
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/798692
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