Abstract: Disclosed herein are methods and compositions for identifying morphogen analogs. Preferred methods rest on the use of test cells comprising DNA defining a morphogen-responsive transcription activating element operatively associated with a reporter gene. In certain embodiments, the methods involve an osteogenic protein 1 (OP-1) responsive transcription activating element. Substances that activate the OP-1 responsive transcription activating element are considered herein likely to be useful for reproducing in vivo effects of morphogens such as OP-1.