IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
artículos
Título:
A loop-to-base processing mechanism underlies the biogenesis of plant microRNAs miR319 and miR159.
Autor/es:
BOLOGNA, NG; MATEOS, JL; BRESSO, EG; PALATNIK, JF
Revista:
EMBO JOURNAL
Editorial:
NATURE PUBLISHING GROUP
Referencias:
Año: 2009 vol. 28 p. 3646 - 3656
ISSN:
0261-4189
Resumen:
The first step in microRNA (miRNA) biogenesis usually involves cleavage
at the base of its fold-back precursor. Here, we describe a
non-canonical processing mechanism for miRNAs miR319 and miR159 in
Arabidopsis thaliana. We found that their biogenesis begins with the
cleavage of the loop, instead of the usual cut at the base of the
stem-loop structure. DICER-LIKE 1 (DCL1) proceeds then with three
additional cuts until the mature miRNA is released. We further show that
the conserved upper stem of the miR319 precursor is essential to
organize its biogenesis, whereas sequences below the miRNA/miRNA(*)
region are dispensable. In addition, the bulges present in the fold-back
structure reduce the accumulation of small RNAs other than the miRNA.
The biogenesis of miR319 is conserved in the moss Physcomitrella patens,
showing that this processing mechanism is ancient. These results
provide new insights into the plasticity of small-RNA pathways.