Located at the center of Chromosome I. "...integrated array (ccIs4251) made up of three plasmids: pSAK4 (myo-3 promoter driving mitochondrially targeted GFP); pSAK2 (myo-3 promoter driving a nuclear targeted GFPLacZ fusion); and a dpy-20 subclone as a selectable marker." pSAK2(myo-3::NgfplacZ), pSAK4(myo-3::Mtgfp), and pMH86 (Fire et al. 1998. Nature391: 806811).. "The multicopy tandem-array character of the ccIs4251 transgene was confirmed by Southern blot analysis (showing 100 copies each of pSAK2 and pSAK4; data not shown). ccIs4251 was obtained following treatment with grays and shows some crossover suppression activity in the center of chromosome I."(Hsieh et al. 1999). "To balance mutations linked to LGI, we used unc-15(e73) with a closely linked GFP transgene (ccIs4251)" (Eckmann et al.2004)