Introducing a New Version of the Cell Cycle

Credits; TheScientist

Inside the human airway, a certain cell type reigns supreme: multiciliated cells, decorated with dozens of hair-like cilia all beating in tandem. These cells are responsible for clearing out foreign bacteria and viruses.

“They break the normal architecture since almost all cells in your body have zero or one cilia each,” said Jeremy Reiter, a developmental geneticist at the University of California, San Francisco. “And whenever an individual cell type does something cool or unexpected, it’s an interesting subject for figuring out how that happens.”

Scientists have long been curious about how cells become multiciliated. Other researchers had previously discovered that several genes that were strongly linked to the canonical cell cycle were reused during the differentiation process for multiciliated cells. Reiter and his team wanted to find out how exactly the cell cycle might be related to differentiation in these special cells. In work recently published in Nature, the team found that these multiciliated cells actually leveraged a previously unknown variant of the cell cycle that they named the “multiciliation cycle.” This research, scientists said, could be useful for better understanding processes like cancer in which the cell cycle also goes awry.

To better understand how the multiciliation cycle worked, the scientists first identified changes in gene expression as the cells differentiated from stem cells into multiciliated cells. “The classic mitotic kinases that regulate division normally were expressed really nicely and sequentially during differentiation of multiciliated cells,” said Semil Choksi, a coauthor and postdoctoral researcher in Reiter’s lab. This sequential expression followed the phases of the traditional cell cycle: G0/G1 (the cell grows larger), S (the cell replicates its DNA), and G2/M (the cell prepares for division and then splits).

While the multiciliation cycle followed the transcriptional phases of the traditional cell cycle, DNA replication did not occur and the cells did not end up dividing. Instead, they grew a bunch of cilia. To figure out what might be driving these differences, the scientists sifted through the genes that were differentially expressed between this variant cell cycle and the traditional cell cycle.

 

 

By Maggie Chen

Article can be accessed on: The Scientist