Biochemical controls: of specialized cell reproduction (Introduction)

by David Turell , Friday, September 06, 2024, 19:13 (10 days ago) @ David Turell

Specific proteins found:

https://www.the-scientist.com/introducing-a-new-version-of-the-cell-cycle-72121

"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.”

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"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.”2 This research, scientists said, could be useful for better understanding processes like cancer in which the cell cycle also goes awry.

***

"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.

"They found that one factor, called E2F7, was expressed at higher levels in the multiciliation cycle. When the team knocked out E2F7 in mice, they found that the multiciliated cells in these mice had significantly increased markers of DNA synthesis, indicating that the multiciliation cycle in these mutated cells had shifted to be more like the canonical cell cycle.

"Interestingly, these E2F7 knockout mice also had hydrocephalus, an abnormal buildup of fluid in the brain. This was due to the dysfunction of multiciliated cells in the brain, which were unable to adequately clear out fluid. When the scientists examined all the multiciliated cells in more detail, they found that the cells had fewer cilia. And instead of the neat phases of sequential gene expression found in normal multiciliated cell differentiation, the cell cycle-related genes expressed by these mutated cells melded into each other, without a distinct transcriptional change going from the S phase into the G2/M phase.

"These findings demonstrate the importance of E2F7 as one of the key factors driving the multiciliation cycle."

Comment: once again, we see a very specified protein co. Only design could produce this result in controlling a genetic mechanism by a single protein factor.