Arabidopsis contains six E2F genes: E2Fa-E2Fc possess all the features of typical animal and plant E2Fs while E2Fd-E2Ff are atypical insofar as they are characterized by the presence of a duplicated DNA-binding domain allowing binding to E2F sites without interactions with a DP partner. E2Fa and E2Fb are activators of E2F-dependent genes while E2Fc is a repressor. Arabidopsis plants overexpressing E2Fa (E2FaOE) have shown increased expression of E2Fb while we have recently demonstrated that in E2FbOE plants the content of E2Fa protein was reduced. This suggested an interplay between activator E2Fs in cell cycle progression. We are now analyzing the consequences of downregulating E2Fb. To gain insight into the role of E2Fd/DEL2, during cell division cycle and development, we have overexpressed and silenced E2Fd in transgenic plants. We found that E2Fd exerts a positive influence on the proliferative activity of dividing cells. This unexpected result derives from repression of E2Fc and RBR gene expression and activation of E2Fa. Thus, our data support the notion of a complex interplay between E2F members forming a regulatory network that involves activator as well as atypical E2Fs.

Interplay between typical and atypical Arabidopsis E2Fs in cell cycle progression and development

MAGGIO, CATERINA;CONCIA, LORENZO;LONGONI, PAOLO;CELLA, RINO
2007

Abstract

Arabidopsis contains six E2F genes: E2Fa-E2Fc possess all the features of typical animal and plant E2Fs while E2Fd-E2Ff are atypical insofar as they are characterized by the presence of a duplicated DNA-binding domain allowing binding to E2F sites without interactions with a DP partner. E2Fa and E2Fb are activators of E2F-dependent genes while E2Fc is a repressor. Arabidopsis plants overexpressing E2Fa (E2FaOE) have shown increased expression of E2Fb while we have recently demonstrated that in E2FbOE plants the content of E2Fa protein was reduced. This suggested an interplay between activator E2Fs in cell cycle progression. We are now analyzing the consequences of downregulating E2Fb. To gain insight into the role of E2Fd/DEL2, during cell division cycle and development, we have overexpressed and silenced E2Fd in transgenic plants. We found that E2Fd exerts a positive influence on the proliferative activity of dividing cells. This unexpected result derives from repression of E2Fc and RBR gene expression and activation of E2Fa. Thus, our data support the notion of a complex interplay between E2F members forming a regulatory network that involves activator as well as atypical E2Fs.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11571/32553
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