Functional Specialization of the Plant miR396 Regulatory Network through Distinct MicroRNA?Target Interactions

DEBERNARDI, JUAN MANUEL; RODRIGUEZ VIRASORO, RAMIRO ESTEBAN; MECCHIA, MARTIN; PALATNIK, JAVIER

PLOS GENETICS

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2012 vol. 8 p. 1 - 14

1553-7390

Plants and other multicellular organisms need precisespatio-temporal control of gene expression, and thisregulatory capacity depends, in part, on small RNAs.MicroRNAs (miRNAs) are one class of ,21 nt small RNAsthat originate from endogenous fold-back precursorsfound in plants and animals. They recognize complementarytarget sites in target mRNAs and guide them tocleavage or translational arrest. Studies of conservedmiRNA networks in Arabidopsis and other plants haverevealed that they fulfill essential regulatory roles. Most ofthe ancient miRNAs regulate transcription factors involvedin plant development and hormone signaling. Here, wecharacterize the miR396 regulatory network. While miR396regulates GRF transcription factors, at least in angiospermsand gymnosperms, this miRNA additionally regulatesanother transcription factor of the bHLH class but only inArabidopsis thaliana and closely related species. Mostconspicuously, the regulation of both conserved and newtargets is important for leaf development in Arabidopsis.We also show that miRNA variants can exist in certainspecies and that they can display an enhanced activitytowards their targets. In summary, we propose thatconserved miRNA regulatory networks might expand theirfunctions by the recruitment of additional targets as wellas by slight variations in the small RNA sequences.