The GFP open reading frame was inserted into exon 1 beginning at the initiator ATG of the Scx gene and replacing most of the first exon. The transgene construct retains the splice donor sequences of exon 1 such that the transcripts of the transgene are spliced to include exon 2. The construct was injected into fertilized eggs and 2 lines were generated that showed robust expression in tendons and tendon progenitors. One line was found to be homozygous viable and was propagated for detailed analysis. (J:121561)