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Professor Maria Helena Goldman seminar

Seminar
29 January 2013, 11am
at the James Hutton Institute, Dundee
for scientists, researchers and other interested parties
2013 Seminar Programme logo

Professor Maria Helena Goldman, University of Sao Paulo, Brazil, will give a seminar "SCI1, a pistil-specific inhibitor of cell proliferation, is probably also involved in RNA processing" at the James Hutton Institute in Dundee. It will be broadcast live to the Aberdeen site.

Abstract

The success of plant reproduction depends on the appropriate development of the reproductive organs which involves specific regulatory networks. We have characterised a novel stigma/style expressed gene encoding a small lysine-rich protein.

Real time RT-PCR and in situ hybridisation experiments showed that it is a tissue-specific developmentally regulated gene. The RNAi and over-expression transgenic plants showed stigmas/styles with remarkably enlarged and reduced areas, respectively, which we have demonstrated that occurs due to differences in cell numbers.

Based on these phenotypes, this gene was designated SCI1 (Stigma/style Cell-cycle Inhibitor 1). Furthermore, the differences in cell division affected the differentiation timing of the stigmatic papillar cells, showing that their differentiation is coupled to stigma cell divisions. Fluorescence microscopy with SCI1-GFP protein fusion demonstrated its nuclear localisation, which is confined to the nucleolus and splicing speckles. To study how SCI1 controls cell proliferation/differentiation, we constructed and screened a yeast two-hybrid stigma/style cDNA library using SCI1 as bait.

Additionally, pull down experiments using recombinant SCI1 and stigma/style proteins were performed. These experiments identified several putative interaction proteins: a cyclin-dependent kinase, a MAPK, a calcium-dependent protein kinase, a DEAD-box protein, two 14-3-3 proteins, two phosphatases, some RNA-binding proteins and several unknown proteins. Bimolecular fluorescence complementation and co-immunoprecipitation assays have already confirmed some of these interactions.

Taken together, our results revealed a tissue-specific inhibitor of cell proliferation in plants and suggest that other tissue-specific cell-cycle regulators may exist and be responsible for the fine tuning of organogenesis in plants. Additionally, the co-localisation of SCI1 with CypRS64, a splicing factor, and the identified SCI1 interaction partners suggest that it may be involved in RNA processing.

Biography

Maria Helena holds a degree in Biological Sciences from the Federal University of Rio de Janeiro (1984), MSc in Agronomy (Plant Breeding and Genetics) by ESALQ - University of São Paulo (1988) and Ph.D. in Genetics and Molecular Biology - Rijksuniversiteit Gent - Belgium (1993). She has held a post-doctorate (1994) at Rutgers - The State University of New Jersey (USA) and obtained the title of a lecturer at USP in 2010.

She is currently Associate Professor at the University of São Paulo with experience in the area of genetics, with an emphasis in Molecular Genetics of Plants, acting on the following topics:

  • flowering
  • plant breeding, with emphasis on the development of the pistil and pollen-pistil interaction
  • expression of heterologous proteins of biotechnological interest.

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The James Hutton Research Institute is the result of the merger in April 2011 of MLURI and SCRI. This merger formed a new powerhouse for research into food, land use, and climate change.