(
fust-1a-mut::mRFP) or isoform b (
fust-1b-mut::GFP) were constructed so that only the other isoform can be expressed. Co-injection of the two plasmids in wild-type N2 strain showed that the two isoforms of FUST-1 were co-expressed in the nuclei of the same cells: neurons and intestinal cells. Interestingly, in early eggs, FUST-1A was expressed earlier than FUST-1B.