A mechanistic link between STM and CUC1 during Arabidopsis development

SPINELLI, SILVANA V.; MARTIN, ANA P.; VIOLA, IVANA L.; GONZALEZ, DANIEL H.; PALATNIK, JAVIER F.

PLANT PHYSIOLOGY.

AMER SOC PLANT BIOLOGISTS

Lugar: Rockville; Año: 2011 vol. 156 p. 1894 - 1904

0032-0889

The KNOXI transcription factor SHOOT MERISTEMLESS (STM) is required to establish and maintain the Arabidopsis apical meristem, while the meristem boundaries are determined by CUP SHAPED COTYLEDON (CUC) transcription factors. In many species, these genes interact also during leaf morphogenesis and sculpt organs with different shapes. Here, we study the relation between STM and CUC genes in Arabidopsis thaliana. We demonstrate that the induction of STM causes a rapid and significant up-regulation of CUC1, which is specific and independent of other meristem regulators. We further show that the regulation of CUC1 by STM is direct and identify putative binding sites in its promoter. Continuous expression of STM in Arabidopsis leaf primordia also causes the activation of CUC2-3, as well as microRNA MIR164a, which provides a negative feedback-loop by post-transcriptionally regulating CUC1 and CUC2. The results show new insights into the mechanistic links between KNOXI and CUC transcription factors.