2 TRANSCRIPTS WITH DIFFERENT SIZES DERIVED FROM A RICE HOMEOBOX GENE,OSH1

A rice homeobox gene, OSH1, contains two functionally independent prom oters which generate a larger transcript and a smaller transcript. In Ambidopsis, each promoter can drive the expression of a reporter gene in a different manner, indicating that the expression of different siz ed transcripts is independently regulated by each promoter. Over-expre ssion of the larger transcript in transformed plants caused altered mo rphologies (Matsuoka et al., Plant Cell, 1993, 5, 1039-1048); in contr ast, over-expression of the smaller transcript did not cause any morph ological changes. The results suggest that the product of the smaller transcript fails to alter the expression of its target gene(s) in the transformants, while that of the larger transcript is capable of alter ing the expression of its target gene(s). (C) 1996 Academic Press, Inc .