Multiple RNA recognition patterns during microRNA biogenesis in plants

BOLOGNA, NG; SCHAPIRE, AS; ZHAI, J; CHOROSTECKI, U; BOISBOUVIER, J; MEYERS, BC; PALATNIK, JF

GENOME RESEARCH

COLD SPRING HARBOR LAB PRESS

Año: 2013 p. 1675 - 1689

1088-9051

MicroRNAs (miRNAs) derive from longer precursors with fold-back structures. While animal miRNA precursors havehomogenous structures, plant precursors comprise a collection of fold-backs with variable size and shape. Here, we designan approach to systematically analyze miRNA processing intermediates and characterize the biogenesis of most of theevolutionarily conserved miRNAs present in Arabidopsis thaliana. We found that plant miRNAs are processed by fourmechanisms, depending on the sequential direction of the processing machinery and the number of cuts required torelease the miRNA. Classification of the precursors according to their processing mechanism revealed specific structuraldeterminants for each group. We found that the complexity of the miRNA processing pathways occurs in both ancient andevolutionarily young sequences and that members of the same family can be processed in different ways. We observed thatdifferent structural determinants compete for the processing machinery and that alternative miRNAs can be generatedfrom a single precursor. The results provide an explanation for the structural diversity of miRNA precursors in plants andnew insights toward the understanding of the biogenesis of small RNAs.