Nature Biotechnology pp 411 - 417

In a finding that will energize research into new treatments for hair loss, stem cells in mouse hair follicles have been shown to regenerate new hair and hair follicles after being implanted into the skin of mice. Writing in the April issue of Nature Biotechnology, George Cotsarelis and colleagues also show that the stem cells can turn into various types of skin cells.

Although scientists have suspected that hair follicles contain stem cells, the new work uses sophisticated cell labeling techniques in transgenic mice to isolate these cells and prove conclusively that they develop into all the mature cell types of the hair follicle and are therefore bona fide stem cells. When the stem cells were mixed with skin cells and transplanted into the skin of immunodeficient mice, they spontaneously grew into fully formed hair follicles that produced hair. The researchers also identified a set of genes that are 'turned on' in the stem cells, providing many new potential targets for altering hair growth. The isolation of hair follicle stem cells holds promise for the development of new approaches to treating hair loss and other disorders of the hair and skin.

Nature Biotechnology pp 435 - 439

Researchers have reduced all the components of a molecular biology laboratory needed to isolate genetic material to a chip the size of a dime. Their 'lab on a chip' allows automatic isolation and processing of genetic material from a single cell. In a collaborative effort, scientists have designed a tiny device containing a series of microchambers and interconnecting plumbing that fully automates the process of isolating genetic material. Stephen Quake and his colleagues describe their nanoliter-scale nucleic acid processor in the April issue of Nature Biotechnology and show how it can be applied to analyze DNA as well as mRNA. Although isolated stages of molecular biology protocols have been miniaturized before, this is the first time an entire procedure has been completely 'shrunk' from start to finish.

Nature Biotechnology pp 455 - 458

Significant public concern surrounds the presence of antibiotic and herbicide resistance (marker) genes that are commonly used in genetically modified (GM) plants. By hooking up these marker genes to transgenes, researchers can identify plants that have incorporated transgenic DNA.

In the April issue of Nature Biotechnology, Torgny Näsholm and his colleagues come up with a system that can select GM plants without the need for of either antibiotics or herbicides. Instead of using an antibiotic or herbicide resistance gene as a marker, the researchers rely on a gene encoding an enzyme that metabolizes amino acids that are mirror images of natural amino acids. The marker allows plants to thrive in the presence of normally toxic mirror amino acids (positive selection) and die when treated with otherwise non-toxic mirror-image amino acids (negative selection). Using the same gene to promote growth or cause death, depending on the treatment, provides an elegant system for selecting GM plants.

The new marker system provides an alternative to the limited range of existing selection markers for generating transgenic plants. European legislation requires the phasing out of GM crops containing selectable markers conferring resistance to clinically used antibiotics by 2004.