Lighting up vertebrate development

Novel labelling technique illuminates synchronous gene expression.

Tweaking current fluorescence-labelling techniques for the detection of biological molecules has generated the first system for viewing expression of several genes at once in a vertebrate embryo, report researchers at the University of Utah, US.

Pinpointing the genes that act together as an animal develops will shed light both on normal development and on the genetic abnormalities underlying birth defects, they say.

The method calls on three current techniques of gene detection: in situ hybridisation, used to detect DNA and RNA in individual cells; immunohistochemistry, in which antibodies detect antigens that are linked to genes; and tyramide signal amplification (TSA), which amplifies fluorescent dyes.

Combining and developing the techniques has resulted in a system that allows researchers to watch the expression of three genes simultaneously in a single chick embryo, even in a single cell. ’Since genes rarely act alone, this in itself will be helpful in understanding developmental processes,’ says lead researcher Teri Jo Mauch.

Until now, such a system had only been possible in lower animals, such as fruit flies. Transferring the technology to higher animals never worked because the method used in fruit flies used a biotin-streptavidin label. Biotin and avidin occur naturally in higher animals, says Mauch, so rather than having molecules of interest light up ’the whole embryo lights up’. The team swapped the biotinylated probe for a dinitrophenol-labelled probe.

Chick embryos offer a good model for human kidney development as their organs develop similarly, says Mauch. ’We’re already applying [the new technique] to our studies investigating early kidney development.’

Bea Perks