Microbiology - Stem Cells

by Krista Conger

Like homing in to an elusive radio frequency in a busy city, human embryonic stem cells must sort through a seemingly endless number of options to settle on the specific genetic message, or station, that instructs them to become more-specialized cells in the body (Easy Listening, maybe, for skin cells, and Techno for neurons?). Now researchers at the Stanford University School of Medicine have shown that this tuning process is accomplished in part by restricting the number of messages, called transcripts, produced from each gene.

Read more: Scientists First to Identify Wide Variety of Genetic Splicing in Embryonic Stem Cells

Microbiology - Stem Cells

Tiny circles of DNA are the key to a new and easier way to transform stem cells from human fat into induced pluripotent stem cells for use in regenerative medicine, say scientists at the Stanford University School of Medicine. Unlike other commonly used techniques, the method, which is based on standard molecular biology practices, does not use viruses to introduce genes into the cells or permanently alter a cell's genome.

It is the first example of reprogramming adult cells to pluripotency in this manner, and is hailed by the researchers as a major step toward the use of such cells in humans. They hope that the ease of the technique and its relative safety will smooth its way through the necessary FDA approval process.

Read more: Virus-free Technique Enables Scientists to Easily Make Stem Cells Pluripotent, Moving Closer to Possible Human Therapies

Microbiology - Stem Cells

Even Superman needed to retire to a phone booth for a quick change. But now scientists at the Stanford University School of Medicine have succeeded in the ultimate switch: transforming mouse skin cells in a laboratory dish directly into functional nerve cells with the application of just three genes. The cells make the change without first becoming a pluripotent type of stem cell — a step long thought to be required for cells to acquire new identities.

The finding could revolutionize the future of human stem cell therapy and recast our understanding of how cells choose and maintain their specialties in the body.

Read more: Dramatic Transformation: Researchers Directly Turn Mouse Skin Cells into Neurons, Skipping IPS Stage

Microbiology - Stem Cells

Monya Baker

Ascl2, a transcription factor and Wnt target, switches on a stem cell program in the gut

In the search for what makes a stem cell a stem cell, Hans Clevers and colleagues at Hubrecht Institute-KNAW, the Netherlands, have found a transcription factor expressed uniquely in the gut¹. Deletion of the gene, called Achaete scute-like 2 (Ascl2), completely ablates stem cell activity. Activating the gene in non-stem cells causes the cells to take on stem cell characteristics, including making stem cell markers and reproducing the structures and specialized cell types that normal intestinal stem cells produce.

Read more: Intestinal Stem Cells : One Gene to Rule Them All

Microbiology - Stem Cells

by Monya Baker

Rat pluripotent stem cells could bring knock-out rats, reprogramming insights, and a larger menagerie of stem cells.

A quartet of papers in December describe the production of rat pluripotent stem cells, both from rat embryos and from the genetic manipulation of cultured rat cells.

The rat embryonic stem cells were derived by research teams led by Austin Smith in Cambridge, UK and Qi-Long Ying of the University of Southern California, Los Angeles. They mark the first of many attempts to create ES cells that, when mixed with a normal rat embryo, can contribute to the germline in the resultant rats. Though neither team has yet produced a knockin or knockout rat, Ying believes this could happen in less than a year.

Read more: Big Potential in Rat Pluripotent Stem Cells