Single-Cell Imaging Watches Cell’s Clock - (11/13/12)
Scientists used an imaging technique to show how cells in Zebra fish embryos line up in the right place and time to determine their next phase in life. They discovered how embryonic cells cooperate with neighboring cells and segment to later form into other things like muscle or a vertebrae. In order for segments to form properly, neighboring cells need to synchronize their cycles of high and low signal reception. This is just like the circadian rhythms in humans but on a scale of minutes rather than hours. The gene activation resulting from the synchronized cycles determines if the segments will form properly.
How do the cells know how to synchronize? This stems from a messaging system called a Notch signaling pathway. The Notch signal maintains the synchronization, without this each cell can still oscillate just fine but are unable to synchronize. They describe the segmented cells forming into tissues, called somites, as ‘the wave’ soccer fans in a stadium would do. Genes are first activated which create proteins that eventually move forward with the ‘wave’ and inhibit those active genes. Every 30 minutes or so, as the ‘wave’ moves forwards, a new somite is created and this will continue until all the necessary somites are made. Much like the ‘wave’, the neighboring people (or segments) must be in-sync for this to happen correctly. The lowest point in the ‘wave’ is where the least gene expression occurs and also happens to be where cells divide indicating that cell division is not random.
Am I the only one that thinks this is magnificent? Anyway, hopefully further research in this area will lead to advances in cell biology and understanding of how different tissues arise from this beautiful synchronization of cells.
