IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Characterization of the microRNA miR396 regulatory network in plants
Autor/es:
RODRIGUEZ VIRASORO, RAMIRO ESTEBAN; DEBERNARDI, JUAN MANUEL; MECCHIA, MARTIN; PALATNIK, JAVIER
Lugar:
Madison, WI
Reunión:
Congreso; 22nd International Conference on Arabidopsis Research; 2011
Resumen:
Leaf primordia are initiated by recruiting cells from the peripheral zone of the shoot apical meristem. Then, extensive mitosis proceeds until cells begin to enlarge. This process is regulated by the concerted action of various transcription factor networks, among them the GROWTH REGULATING FACTORS (GRFs). Mir396 regulates seven out of the nine transcription factors of the GRF family in Arabidopsis. Overexpression of miR396 leads to downregulation of GRFs and reduced leaf cell number. Conversely, high levels of GRF2 activity increases cell proliferation in leaves. Using different reporter constructs, we determined that miR396 is essential to establish a dynamic spatio-temporal pattern of GRF2 expression, which in turn coincides with the activity of cell proliferation markers. Analysis of miR396 and its targets in various plants species revealed the existence of novel miRNA-target pairs. First, particular miR396 variants are expressed only in certain species. Expression of these versions in Arabidopsis indicated that they are stronger repressors of the GRFs than the Arabidopsis miR396 variants. Second, a search for novel miR396 targets revealed that a basic-helix-loop-helix transcription factor is regulated only in a group of Brassicales. The importance of miR396-mediated repression of this bHLH for normal Arabidopsis development will be discussed.