• Researchers at the Centre for Genomic Regulation (CRG) in Barcelona have identified a sophisticated molecular mechanism essential for the maintenance of stem cells, embryonic development and cancer.
• The study has been published in the prestigious international journal Nature Structural & Molecular Biology.

Barcelona, 31th October, 2012. Embryonic stem cells are responsible for generating every kind of cell in an organism, so the molecular mechanisms responsible for maintaining the identity of these cells and their capacity to generate tissues must be very precisely controlled.
Epigenetics is the branch of biology that looks at the heritable changes in gene expression not involving an alteration or mutation of the DNA. Epigenetic mechanisms are those that determine the specificity of each cell type making up the tissues of an individual. The Polycomb protein complex is a group of proteins involved in the epigenetic regulation of cells. It is essential for proper embryonic development, and its function is frequently altered in cancer. Therefore, knowing how the Polycomb complex functions is essential for understanding cancer and embryonic development. Researchers from the CRG have discovered both how Polycomb proteins bind to DNA and how they work in the cell.
Cecilia Ballaré, first author of the study and researcher in the Epigenetic Episodes and Cancer group at the CRG led by Dr. Luciano Di Croce, explains that “the Polycomb protein complex is responsible for regulating the action of the genes related to cell differentiation, but until now we didn’t understand how it did it. We have discovered that the protein Phf19 leads the Polycomb complex to specific locations in the DNA, thereby controlling the expression of certain genes essential for maintaining the identity and proper function of the stem cells.”
Dr. Di Croce adds that “it was a surprise to find that protein Phf19 is like a compass telling the Polycomb complex where to work on the stem cells. It is also the first time that a connection has been demonstrated between a molecular protein (Phf19) that binds to an epigenetic mark related to gene expression, and a molecular mechanism essential for gene suppression”.
Luciano Di Croce, head of the research group at the CRG, has been studying these complexes and their role in embryonic development and tumour progression since his arrival at the CRG. In a study published earlier this year, which made the cover of the prestigious international journal Cell Stem Cell, the laboratory of Dr. Di Croce showed that the function of a variant of the Polycomb complex is essential for maintaining the proper functioning of stem cells.
Dr. Di Croce is currently coordinating the project 4DCellFate, funded by the European Commission and involving 13 organisations, including universities, research centres and private companies.
Scientists from the CRG, Stanford University, Harvard Medical School and the European Molecular Biology Laboratory EMBL, Heidelberg, all participated in the study which was funded by the Ministry of Science and Innovation and the European project www.4dcellfate.org.
Reference:
Ballaré, C. et al. Phf19 links methylated Lys36 of histone H3 to regulation of Polycomb activity. Nature Structural & Molecular Biology (2012). AOP 28/10/12. doi:10.1038/nsmb.2434
For further information:
Juan Saraua – Press Officer – juan.sarasua@crg.eu