Lights, camera, mitosis!

Cells multiply and divide millions of times each day in our bodies, but researchers still don't know exactly which genes are involved in mitosis. The linkurl:MitoCheck;http://www.mitocheck.org/ consortium, a European research collaboration, aims to change that. Like sports trainers filming individual players to dissect the finer points of their games, MitoCheck researchers capture individual cells dividing to tease apart the contributions of individual genes to the process of mitosis. The consortium has taken videotaping to a whole new level by generating 190,000 time-lapse photographs of mitosis, meticulously filming the inactivation of approximately 21,000 genes, one at a time, to determine their effects on cell division.

Their efforts may shed new light on tumorigenesis. "We now have much better molecular inventory of one of the important steps in early development of human cancers," says linkurl:Jan Ellenberg;http://www.embl.de/ExternalInfo/ellenberg/homepage/labmembers.html a cell biologist at the European Molecular Biological Laboratory (EMBL) and MitoCheck coordinator. "We now have many new potential biomarkers to diagnose cancer in the future but also many new potential drug targets to develop new therapies." Ellenberg adds that the goal of MitoCheck consortium, which was launched in 2004, is to more fully understand mitosis "because it is one of the most fundamental processes of life." The MitoCheck team, comprising scientists from the EMBL and other European research institutions from Italy to the UK, use siRNA mircoarrays and time lapse microscopy to create the mitosis films. HeLa cells are tagged with glow in the dark proteins, for easier viewing. Genes are knocked down out one at a time using siRNAs, and mitosis is allowed to progress. The researchers relies on computational analysis of the movies to identify what effect the missing genes have on cell division. Movies are flagged if mitosis is not natural, and the researchers even group the films by similar mishaps including cell death, nuclei location, and decondensation failures, among others. Thus far, the team has identified about 572 genes involved in the process of mitosis. Most of those were known previously, but several surprises resulted. "This approach is predicated on the fact that the only way one can say whether or not a particular gene is involved in cell division is to film cells as they divide after knocking the gene down (or in mutants)," says linkurl:Conly Rieder,;http://www.wadsworth.org/resnres/bios/rieder.htm cellular and molecular biologist at the New York State Department of Health's Wadsworth Center who is not involved with the MitoCheck consortium. Programming the computers used to classify mitotic phases was a long and difficult task for linkurl:Beate Neumann,;http://www.embl.de/almf/almf_services/contact/neumann/ an EMBL biologist working on the project. "It took us more than 2 years to develop image processing software," she says.

linkurl:Thomas Walter,;http://www.embl.de/research/units/cbb/ellenberg/members/?s_personId=4160 an electrical engineer at EMBL worked with Neumann to create the program. "Walter programmed the software and I gave the input for the different morphological classes," adds Neumann. Due to the size of the data sets generated by analyzing the movies, the initial processing time was about 3 months. In this time Neumann looked at nearly 20,000 movies get a clear picture of different morphologies held by cells undergoing mitosis. Neumann says that the program failed twice before succeeding on the third try. "You can't imagine how happy we were after seeing the results of the image processing after the third attempt," she recalls. Neumann said that the group chose to make the movies and the data they generated public because they wanted scientists to "have the possibility to look at the raw data and not at processed data or just numbers in a text file." Nuemann finds looking at the videos to be more informative than looking "just a number in a manuscript or even a description of a phenotype." All of MitoCheck's movies are available online at the project's linkurl:website,;http://www.mitocheck.org/ where anyone can query the database by gene name, RNA name, or mitotic phenotype. Rieder says that it's "very cool that the database generated has been made freely accessible to other researchers--instead of hidden away behind the wall of individual labs."
**__Related stories:__***linkurl:The successful squish;http://www.the-scientist.com/article/display/56245/
[January 2010]*linkurl:Divide, Conquer;http://www.the-scientist.com/article/display/56172/
[December 2009]*linkurl:New cell cycle complexities;http://www.the-scientist.com/blog/display/55659/
[23rd April 2009]