Control of expression and autoregulation of AGL15, a member of the MADS-box family

AGL15 is an Arabidopsis thaliana MADS-domain regulatory factor that not only preferentially accumulates during embryogenesis but is also expressed at lower levels after the completion of germination. To better understand the control of expression of AGL15, a series of 5′ and internal deletions within the regulatory regions of AGL15 was generated. Regions important for the level of expression, including a region involved in expression in response to auxin, were identified. Additionally, AGL15 expression was found to respond to AGL15 accumulation amounts and to altered forms of AGL15. This feedback loop is at least in part due to direct regulation, as assessed by in vivo and in vitro binding of AGL15 to its own regulatory regions and by site-directed mutagenesis studies.