domenica 12 luglio 2009

New Insights Into Formation Of The Centromere, A Key Cellular Structure In Powering And Controlling Chromosome Segregation

ScienceDaily (July 13, 2009) — Lars Jansen* has described the formation of the centromere, a key cellular structure in powering and controlling chromosome segregation and accurate cell division.
A new Nature Cell Biology paper, published in collaboration with a group at Stanford University School of Medicine, provides insights into the scaffold of proteins that ensures accurate segregation of chromosomes during cell division - a fundamental step to ensure that daughter cells have the same genetic information as their mother, with reduced risk of cancer.
When segregating, chromosomes attach and move along proteins tracks (the mitotic spindle), from the centre of the cell to the poles. The centromere is the area of the chromosome that directs this attachment by controlling the assembly of a scaffold of proteins (called the kinetochore), which tether the chromosome to the spindle, and power its movement along the protein track. The location of the centromere on the chromosome is marked by the presence of a protein, called CENP-A, but how this protein is recognised by the other components of the cell to orchestrate the assembly of the centromere was not understood - until now.
Using a newly developed assay, Lars and his colleagues were able to identify the protein that triggers the assembly of the centromere. It's called CENP-N. According to Mariana Silva, a PhD student in the lab, 'When we depleted CENP-N in cells, the centromere did not assemble correctly and chromosomes segregated abnormally, leading to situations similar to cancer'.
This study shows the applicability of this new assay and open doors to future studies into centromere assembly and structure.
*Lars Jansen moved from California to the Instituto Gulbenkian de Ciência (IGC), in Portugal, last year to head the Epigenetic Mechanisms group.
An EMBO installation grant, of 50,000 euro per year, for a maximum of five years has been awarded.
Adapted from materials provided by Instituto Gulbenkian de Ciencia, via EurekAlert!, a service of AAAS.

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