High impact information on AFO

• FIL encodes a protein carrying a zinc finger and a HMG box-like domain, which is known to work as a transcription regulator [1].
• The ae3 as2 double mutant displayed severely abaxialized leaves, which were accompanied by elevated levels of leaf abaxial promoting genes FILAMENTOUS FLOWER, YABBY3, KANADI1 (KAN1), and KAN2 and a reduced level of the adaxial promoting gene REVOLUTA [2].
• CRABS CLAW (CRC), a member of the YABBY gene family, is required for nectary and carpel development [3].
• The enhanced phenotype in the fil ap1 and the fil lfy double mutants suggests that the FIL protein may work together with AP1 and LFY proteins [4].
• Novel, localized planes of blade expansion occur in some kanadi loss-of-function genotypes and these ectopic lamina outgrowths are YABBY dependent [5].

Biological context of AFO

• The INO homologues obtained have a portion similar to INO in the predicted amino acid sequences between the conserved zinc finger-like and YABBY domains [6].
• Furthermore, we show that ANT acts with FIL to up-regulate expression of the floral homeotic gene APETALA3 [7].
• Members of three classes of transcription factors in Arabidopsis (Arabidopsis thaliana; the Class III homeodomain/leucine zipper [HD-ZIP] proteins, KANADI proteins, and YABBY proteins) are expressed in either the adaxial or abaxial domain of organ primordia where they confer these respective identities [7].
• Downregulation of the HD-ZIPIII genes allows expression of the KANADI and YABBY genes, which specify abaxial fate [8].

Associations of AFO with chemical compounds

• The FILAMENTOUS FLOWER protein has a zinc finger domain, hydrophobic region, proline-rich region, and a HMG box-like domain [9].
• Analysis of the amino-terminal region of the FILAMENTOUS FLOWER protein suggests that seven cysteine residues at positions 14, 26, 30, 33, 54, 56, and 57, and two histidine residues at positions 18 and 24 contribute to a putative zinc finger motif, Cys-X(3)-His-X(5)-His-X-Cys-X(3)-Cys-X(2)-Cys-X(20)-Cys-X-Cys-Cys [10].
• Gel retardation experiments showed that the FILAMENTOUS FLOWER protein binds to DNA without sequence specificity [9].
• In support of this, substitution of the Cys(56) by alanine suppressed both the zinc release and the multimerization of the FILAMENTOUS FLOWER protein [10].
• Non-sequence-specific DNA binding by the FILAMENTOUS FLOWER protein from Arabidopsis thaliana is reduced by EDTA [9].

Regulatory relationships of AFO

• The alterations in polarity establishment are associated with expansion in the expression domain of the PHB-like genes and reduction in the expression of the previously described abaxial-promoting YABBY genes [11].
• AINTEGUMENTA contributes to organ polarity and regulates growth of lateral organs in combination with YABBY genes [7].

Other interactions of AFO

• Ectopic expression of either FILAMENTOUS FLOWER or YABBY3 is sufficient to specify the development of ectopic abaxial tissues in lateral organs [12].
• In vitro pull-down experiments confirmed the NZZ-FIL interaction [13].
• All YABBY coding regions, except YABBY5, were able to restore outer integument growth in ino-1 mutants when expressed from the INO promoter (PRO(INO)) [14].
• We propose that the initial asymmetric leaf development is regulated primarily by mutual antagonism between KANADI and PHB-like genes, which is translated into polar YABBY expression [5].

Analytical, diagnostic and therapeutic context of AFO

• In situ hybridization clearly demonstrated that FIL is expressed only at the abaxial side of primordia of leaves and floral organs [1].
• Molecular cloning reveals that DL is a member of the YABBY gene family and is closely related to the CRABS CLAW (CRC) gene of Arabidopsis thaliana [15].
• A cysteine residue at position 56 in the FILAMENTOUS FLOWER protein potentially interferes with zinc ligation within the zinc finger and causes this zinc release [10].

References