DIFFERENTIAL TRANSCRIPTION AND EXPRESSION OF ORNITHINE DECARBOXYLASE IN EMBRYOS OF REPLICATED MOUSE LINES DIVERGENTLY SELECTED FOR LEAN BODY-MASS

Embryos of replicated mouse lines divergently selected for high or low lean body mass have been shown to differ approximately twofold in the activity of ornithine decarboxylase during embryogenesis and that thi s difference has been shown to be associated with a restriction enzyme polymorphism in the structural gene [Gray and Tait (1993) Genet, Res, 62, 31-37]. In the present paper we report that the differences in en zyme activity are due to changes in transcription and show that the en zyme produced has the same specific activity in all selected lines, pr ecluding any significant structural change in the enzyme being associa ted with the differences in the structural gene.