Genome complexity: how cells fight infection: (Introduction)

by David Turell , Wednesday, August 17, 2016, 01:44 (2803 days ago) @ David Turell

Cells open up genes to begin the anti-inflammation function:-https://www.sciencedaily.com/releases/2016/08/160816152919.htm-"...scientists show that when immune cells encounter a bacteria, a number of genes become active. During this process, nucleosomes, which coat DNA and essentially block genes, are gone, leaving the genes open and ready to enlist in the fight against bacteria.-"These particular genes are related to inflammation.-***-"'What causes some cells to express these genes while other cells do not?" she asked. "Does the packaging of DNA play a role in deciding which genes are expressed? We believe that it's more about the regulation and the mechanics of how the transcriptional machinery is recruited than the genes themselves."-"Floer likens the process to Michigan winters. In the Midwest, it's always snowing. Finding an open parking space that's not covered with snow becomes a statewide pastime. Complicating matters, imagine that you have an electric car, and you need a special spot. There are only a few of them, and they have to be cleared of snow.
Specifically, the team extracted stem cells involved in inflammation and fighting infections from the bone marrow of mice. They grew them in petri dishes to become mature macrophages, white blood cells that devour any diseased protein in their path. In their experiments, they showed that cell-type specific transcription factors bind to macrophage-specific genes and recruit the nucleosome remodeler -- the cellular snowplows. Once bonded, nucleosome remodelers keep the gene regulatory sites open by clearing away the blizzard of nucleosomes.-"In addition, Floer's team discovered that the remodelers function at these sites long before the genes are expressed and doing their jobs. This means that they are recruited at some point during differentiation of stem cells into their specific, adult cells.-"'We find that as a cell differentiates into a specific cell type, it acquires all of the necessary information early on that dictates its behavior as an adult cell," Floer said.-"The next phase of this research will be expanded genome wide. Floer's team focused only on a handful of genes. Along with tackling an entire genome, the team will experiment with environmental changes during differentiation to see what factors enhance the prevalence of cellular snowplows..."-Comment: Since infections kill, I wonder how these cells develop their capacity to fight infection with potential fatal infections all around. It doesn't seem to be possible step by step.