In this study, we focused on the relationship between leaf of higher plants and thallus of bryophytes. ANGUSTIFOLIA gene of Arabidopsis thaliana (AtAN), first member of the CtBP family in plant, comtrols elongation of leaf cells in the width direction of the leaf. We isolated a homologue of AtAN gene from liverwort Marchantia polymorpha (MpAN). The sequences of total cDNA and the corresponding genomic DNA region were determined. The MpAN gene was predicted to code a protein of 639 residues and had seven exons. The deduced MpAN protein showed an identity of 50% to the AtAN protein. The MpAN protein,however, did not have the Rb-binding motif and nuclear localization signal both which were detected in the AtAN protein. Southern analysis indicated that it was a single-copy gene in the nuclear genome. By Northern analysis using total RNA of thallus, 2.9kb-transcript was detected. To investigate a role of MpAN gene,we produced transgenic Marchantia expressing the CaMV35S promoter linked to the total region and CtBP region of MpAN gene in sense and antisense orientation. In a CtBP transgenic plant, thalli were strongly curled. In a anti-MpAN transgenic plant, rhizoid-like structure arose in the abaxial side of thallus. Studies on relationship between expression of MpAN gene and phenotype of plant are now in progress.