Figure 6.—

Model for Arabidopsis gene function during lateral organ development. The BOP1 and BOP2 genes directly induce AS2 expression and also negatively regulate FIL and YAB3 activity in developing leaves. In addition, the BOP genes repress KNOX1 (BP, KNAT2, KNAT6) expression via an AS2-independent pathway. AS2 and FIL/YAB3 play separate roles in negatively regulating KNOX1 transcription during lateral organ growth. FIL/YAB3 also promote lamina outgrowth along the adaxial–abaxial boundary (shaded arrow) through a KNOX1 independent pathway. AD, adaxial; AB, abaxial.