#brainbow

Crypt Chaos

Your gut churns and digests every day, which is why it needs to regenerate its lining every week. This is made possible by intestinal stem cells that live in crypts in the gut lining. However, if one of these cells develops a mutation that makes it more likely to become cancerous, it can divide to populate an entire region with pro-cancer cells, greatly increasing the risk of cancer. Researchers now use genetic engineering to fluorescently tag pro-cancer mutations in mouse intestinal stem cells to track their descendants. They found cells with mutations in a gene called Rspondin-3 rapidly expanded in adult gut linings, while those with mutations in another gene beta-catenin did not. In Rspondin-3 mutants, crypt cells divided more producing abnormally large intestines, as captured using fluorescent microscopy (pictured, right), when compared to beta-catenin mutants (left). This so-called 'Crainbow' model provides insights into the development of pro-cancer gut tissue.

Written by Lux Fatimathas

Image from work by Peter G. Boone and Lauren K. Rochelle, and colleagues

Division of Surgical Sciences, Department of Surgery, Duke University School of Medicine, Durham, NC, USA

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in Nature Communications, December 2019

Brainbow Connection! Image of the Week – March 11, 2019

CIL:41458 - http://cellimagelibrary.org/images/41458

Description: "Brainbow" zebrafish. Neurons are labeled in multiple colors with "Brainbow" (Nature, 2007) fluorescence microscopy. Three fluorescent proteins (cyan, yellow, and red) are randomly taken up by various neurons, offering a palette of dozens of colors to help scientists follow complex neural pathways. Shown here is a 5-day-old zebrafish larva viewed from the dorsal side, captured using a 20X objective. Fourth Prize, 2008 Olympus BioScapes Digital Imaging Competition®.

Authors: Albert Pan and 2008 Olympus BioScapes Digital Imaging Competition®

-Schoonover, Portraits of the Mind p172

(Turnup for that watermark, go to app.biorender.io to make dope bio figures that probably look better than my own)

so basically they insert a gene construct into an animal that contains genes for several different proteins that fluoresce in specific colors (in this case, red, yellow, and cyan florescent proteins). It’s also set up so that any color expressed turns off the other two colors. They also have sites between each color and at the beginning, that basically mark where the scissors are supposed to cut

Let’s get onto the scissors. These represent a Cre recombinase protein that cuts out marked segments of the genes so, basically randomly, the scissors either cut what’s between the white arrows or what’s between the grey arrows (and in more complicated constructs other things go on but we’re not going there)

So left to right, if you cut between the white arrows, you get yellow and cyan, but yellow turns off cyan (YELLOW!)

Cut out the grey arrows, and you get cyan and thus CYAN

Sometimes Cre doesn’t do anything/work/whatever, in which case we’d get all 3 present, and red would shut down yellow and cyan and thus RED

Now, to get more color variety, they’d insert like 100 of these gene constructs into the genome and then in each cell you would get a random combination of these 3 options. Now we have a way of labeling cells where we can presumably trace them all the way across the brain.

Nature, Meet Nurture

Is it nature or nurture that ultimately shapes a human? Are actions and behaviors a result of genes or environment? Variations of these questions have been explored by countless philosophers and scientists across millennia. Yet, as biologists continue to better understand the mechanisms that underlie brain function, it is increasingly apparent that this long-debated dichotomy may be no dichotomy at all.