Functional Genomics in C. elegans 2:

Expression analysis using reporter genes

(1: Microarray analysis 2: Expression analysis using reporters 3: RNAi)

It is possible to construct transgenic C. elegans strains carrying reporter genes whose expression is driven by the promoter of a chosen gene. The usual reporters are green fluorescent protein (GFP) and betagalactosidase. The betagalactosidase construct used carries a nuclear localisation signal and is thus usually nuclear localised.

The following micrographs are the work of Dr Daphne Gerrits. They show embryo, larval and adult C. elegans expressing betagalactosidase or green fluorescent proteinunder the control of the tyr-1 promoter. tyr-1 encodes a tyrosinase-related protein, that may be involved in cuticle protein crosslinking. It is expressed in hypodermal (=skin) cells that synthesise cuticle. The betagalactosidase was visualised after fixing the nematodes by staining with chromogenic substrate (Xgal). The GFP was visualised in live (anaesthetised) animals using fluorescence microscopy.

Larval nematode just prior to hatch expressing tyrosinase promoter driven GFP

Larval nematode expressing tyrosinase promoter driven GFP

Adult nematode expressing tyrosinase promoter driven GFP

Adult nematode expressing tyrosinase promoter driven betagalactosidase