While wild-type Z600 transcript expression is only detected in 0-4 hr embryos, reporter expression persists in 4-6 hr embryos. Embryonic expression of the reporter construct is first detected at embryonic cycle 13. Uniform expression becomes restricted to dorsal regions, with some ventral expression, by embryonic cycle 14. During germ band extension, the majority of the transcript is in the amnioserosa, with some expression in ventral regions. The construct appears to have the sequences necessary for zygotic and dorsal expression, but appears to lack sequences necessary for ventral and temporal repression.