Research: Germ of an idea

The Blimp1 gene has been identified as a key factor in the development of mouse germ cells (eggs and sperm). It appears to act by preventing primordial germ cells from following a developmental path that turns them into body cells.

Germ cells are special. While other cells of the body last no longer than the lifetime of an organism, germ cells, uniquely, have the potential to seed the next generation. In mice, the cells that will generate germ cells are specified in early development, in response to a signal that about 40 cells receive from their neighbours. Two research groups have identified the Blimp1 gene as an important part of this key cellular decision-making mechanism.

A critical step in this process is the repression of a developmental programme followed by all other body cells (somatic cells). Dr Azim Surani and colleagues in Cambridge, and Dr Elizabeth Robertson and colleagues in Oxford, independently discovered that the Blimp1 gene is central to this repression. In the absence of Blimp1, cells that resemble germ cells develop but do not follow the usual germ cell development pathway, and eventually turn into somatic cells.

Dr Robertson's team studied the role of Blimp1 in knockout mice, which, as well as having other defects, are entirely lacking germ cell precursors. Dr Surani's team also noted disruption to germ cell development in mutant mice. In addition, they used cell-labelling techniques to confirm that cells making Blimp1 in normal embryos are those that turn into germ cells.

The research thus provides important insight into a fundamental biological puzzle: development of the cells that perpetuate a species' existence.

External links

• Ohinata Y et al. Blimp1 is a critical determinant of the germ cell lineage in mice. Nature 2005;436(7048):207–13.
• Vincent SD et al. The zinc finger transcriptional repressor Blimp1/Prdm1 is dispensable for early axis formation but is required for specification of primordial germ cells in the mouse. Development 2005;132(6):1315–25.