RNA Biology

Summary

Plants and other multicellular organisms need a precise spatio-temporal control of gene expression during their development, and to respond to changes in the environment and defend their genome. In part, this regulatory capacity resides at the RNA level through small RNA-directed gene silencing. MicroRNAs are one of the classes of small RNAs that have 21 nt and fulfill essential regulatory roles. They usually recognize target mRNAs by base complementarity and guide them to cleavage or translational arrest. Our laboratory is currently interested in the biogenesis of these small molecules and their specific functions in plants. The experimental approaches aim to address fundamental mechanistic questions using the model system Arabidopsis thaliana, but the lab also seeks to develop tools of practical relevance that can be applied to plants of agronomic importance.

Research Lines

Biogenesis of plant microRNAs

MicroRNAs are distinguished from other small RNAs by their unique biogenesis, which involves a precise excision from the stem of a fold-back precursor located in a long primary transcript. The type III ribonuclease DICER-LIKE1 (DCL1) with the aid of the accessory proteins cleaves the precursors to release the microRNAs. However, plant microRNA precursors come in different sizes and shapes, and we are interested in understanding how these precursors can be processed to generate the mature microRNAs. We have found that many precursors are processed in a base-to-loop direction, while others are processed by a non-canonical loop-to-base mechanism. We use a combination of approaches to study microRNA processing, including the analysis of libraries of random mutant precursors, the identification of processing intermediates with the aid of next generation sequencing techniques, as well as structural studies in collaboration with the groups of Jerome Boisbouvier and Rodolfo Rasia.

MicroRNA networks in plants

In plants, many of the evolutionary conserved miRNAs regulate transcription factors, which in turn play key biological functions. Perturbation of these miRNA regulatory networks, by mutations in microRNAs encoding genes or by interference with their activity usually causes severe developmental defects. We are interested in identifying the targets of plant microRNAs, as well as their biological functions. The lab also focuses in the control of cell proliferation and differentiation by two microRNAs, miR396 and miR319.

Selected Publications

  • Bologna NG, Schapire AL, Zhai J, Chorostecki U, Boisbouvier J, Meyers BC, Palatnik JF. (2013) Multiple RNA recognition patterns during microRNA biogenesis in plants. Genome Res. [Epub ahead of print]
  • Chorostecki U, Crosa VA, Lodeyro AF, Bologna NG, Martin AP, Carrillo N, Schommer C, Palatnik JF. (2012) Identification of new microRNA-regulated genes by conserved targeting in plant species. Nucleic Acids Res.
  • Debernardi, J.M., Rodriguez, R.E., Mecchia, M.A., Palatnik, J.F. (2012) Functional specialization of the plant miR396 regulatory network through distinct microRNA-Target interactions. PLoS Genetics 8, e1002419.
  • Spinelli, S.V., Martin, A.P., Viola, I.L., Gonzalez, D.H., and Palatnik, J.F. (2011). A mechanistic link between STM and CUC1 during Arabidopsis development. Plant Physiol 156, 1894-1904.
  • Mateos, J.L., Bologna, N.G., Chorostecki, U., Palatnik, J.F. (2010). Identification of microRNA processing determinants by random mutagenesis of Arabidopsis MIR172a precursor. Curr Biol 20, 49-54.
  • Rodriguez, R.E., Mecchia, M.A., Debernardi, J.M., Schommer, C., Weigel, D., Palatnik, J.F. (2010). Control of cell proliferation in Arabidopsis thaliana by microRNA miR396. Development 137, 103-112.
  • Bologna, N.G., Mateos, J.L., Bresso, E.G., Palatnik, J.F. (2009). A loop-to-base processing mechanism underlies the biogenesis of plant microRNAs miR319 and miR159. Embo J 28, 3646-3656.
  • Schommer, C., Palatnik, J.F., Aggarwal, P., Chetelat, A., Cubas, P., Farmer, E.E., Nath, U., Weigel, D. (2008). Control of jasmonate biosynthesis and senescence by miR319 targets. PLoS Biol 6, e230.

Grants

  • Howard Hughes Medical Institute (HHMI).
  • Human Frontier Science Program (HFSP).
  • Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT).
  • Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET).

Director

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Palatnik, Javier
Core CCT
Email: palatnik@ibr-conicet.gov.ar
Phone: +54 341 4237070
Office Extension: 659
Laboratory Extension: 613

Researchers

  • Ramiro Rodriguez Virasoro
  • Carla Schommer

Postdoctoral fellows

  • María Florencia Ercoli
  • Belén Moro

Doctoral fellows

  • Matías Beltramino
  • Ana Paula Perrone
  • Antonela Ferela
  • Camila Goldy
  • Julia Baulies
  • Arantxa Rojas

Imágenes

Desarrollamos nuevas metodologías por mutagénesis al azar para estudiar la biogénesis de microARNs en plantas.

El aumento de biomasa en las plantas transgenicas rGRF son uno de los ejemplos de las aplicaciones tecnologicas de los microARNs.