Repression of cell proliferation by miR319-regulated TCP4

SCHOMMER C; DEBERNARDI JM; BRESSO, EG; RODRIGUEZ RE; PALATNIK JF

MOLECULAR PLANT

OXFORD UNIV PRESS

Año: 2014 p. 1 - 12

1674-2052

Leaf development has been extensively studied on a genetic level. However, little is known aboutthe interplay between the developmental regulators and the cell cycle machinery, a link thatultimately affects leaf form and size. miR319 is a conserved microRNA that regulates TCPtranscription factors involved in multiple developmental pathways, including leaf developmentand senescence, organ curvature, and hormone biosynthesis and signaling. Here, we analyze theparticipation of TCP4 in the control of cell proliferation. A small increase in TCP4 activity has animmediate impact on leaf cell number, by significantly reducing cell proliferation. Plants with highTCP4 levels have a strong reduction in the expression of genes known to be active in G2-M phaseof the cell-cycle. Part of these effectsismediated by induction of miR396, which represses GrowthRegulating Factors (GRFs) transcription factors. Detailed analysis revealed TCP4 to be a directregulator ofMIR396b. However, we found that TCP4 can control cell proliferation throughadditional pathways, and we identified a direct connection between TCP4 andICK1/KRP1, a geneinvolved in the progression of the cell-cycle. Our results show that TCP4 can activate differentpathways that repress cell proliferation.