Scientists at European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany created a systematic approach to discovering which genes play a role in cell division. The process involves silencing individual genes and putting the modified cells under a microscope, with a computer image recognition system subsequently analyzing the motion for signs of mitosis. The researchers are now making freely available all the findings and videos from the study.
Of the 22,000 genes in each human cell, almost 600 play a part in mitosis, Ellenberg and colleagues found. To uncover which genes are involved in this process, the scientists developed a new method using high-throughput imaging of living cells. They silenced, or inactivated, each of the 22,000 human genes one by one in a different set of cells, and filmed those cells for 48 hours under a microscope. This generated almost 200,000 time-lapse movies of mitosis. Having a person – or even a group of people – process such vast amounts of information would be almost impossible, so the scientists created a new computer program that analyses the footage and automatically detects what characteristic defects cells display, and in what order. By grouping genes with similar effects – for instance, genes which when inactivated led to cells with 2 nuclei instead of one, after division – they were able to identify genes involved in mitosis, which they confirmed with further experimental assays.
The current study looked at HeLa cells, a widely studied line of cancer cells. Now that they have narrowed the search from a daunting 22,000 to a more manageable 600 genes, the scientists would like to investigate how these same genes act in other cancers and in healthy cells, as such comparisons could help to identify markers which could be used for diagnosis or to help make better-informed treatment decisions.
Nature podcast (relevant part starts at 6:30):
Here’s a video of a normal mitosis followed by a mitosis inhibited by silencing a gene:
Press release: Movies for the human genome…
Abstract in Nature: Phenotypic profiling of the human genome by time-lapse microscopy reveals cell division genes