Contents

11 February 1994
Vol 263, Issue 5148

About The Cover

Gene expression in living cells is often difficult to detect because of limited access of substrates to marker enzymes. Here gene expression in specific neurons of the nematode Caenorhabditis elegans is monitored by the bright green fluorescence of the green fluorescent protein (GFP) from the jellyfish Aequorea victoria. The GFP fills entire neurons, including in one neuron an extended, fanned growth cone visible in the tail end (upper portion) of the nematode. See page 802. [Photo: Martin Chalfie]