Isolation and characterization of the Larix gmelinii ANGUSTIFOLIA ( LgAN ) gene

ANGUSTIFOLIA ( AN ), a plant homolog of C-terminal binding protein, controls the polar elongation of leaf cells and the trichome-branching pattern in Arabidopsis thaliana . In the present study, degenerate PCR was used to isolate an ortholog of AN , referred to as LgAN , from larch ( Larix gmelinii ). The LgAN cDNA is predicted to encode a protein of 646 amino acids that shows striking sequence similarity to AN proteins from other plants. The predicted amino acid sequence has a conserved NAD-dependent 2-hydroxy acid dehydrogenase (D2-HDH) motif and a plant AN-specific LxCxE/D motif at its N-terminus, as well as a plant-specific long C-terminal region. The LgAN gene is a single-copy gene that is expressed in all larch tissues. Expression of the LgAN cDNA rescued the leaf width and trichome-branching pattern defects in the angustifolia-1 ( an-1 ) mutant of Arabidopsis , showing that the LgAN gene has effects complementary to those of AN . These results suggest that the LgAN gene has the same function as the AN gene.