SAP ranscription Factor Family
A recessive mutation in the Arabidopsis STERILE APETALA (SAP) causes severe aberrations
in inflorescence and flower and ovule development. In sap flowers, sepals are
carpelloid, petals are short and narrow or absent, and anthers are degenerated.
Megasporogenesis, the process of meiotic divisions preceding the female gametophyte
formation, is arrested in sap ovules during or just after the first meiotic division.
More severe aberrations were observed in double mutants between sap and mutant alleles
of the floral homeotic gene APETALA2 (AP2) suggesting that both genes are involved in
the initiation of female gametophyte development. Together with the organ identity gene
AGAMOUS (AG) SAP is required for the maintenance of floral identity acting in a manner
similar to APETALA1. In contrast to the outer two floral organs in sap mutant flowers,
normal sepals and petals develop in ag/sap double mutants, indicating that SAP
negatively regulates AG expression in the perianth whorls. This supposed cadastral
function of SAP is supported by in situ hybridization experiments showing ectopic
expression of AG in the sap mutant. We have cloned the SAP gene by transposon tagging
and revealed that it encodes a novel protein with sequence motifs, that are also
present in plant and animal transcription regulators. Consistent with the mutant
phenotype, SAP is expressed in inflorescence and floral meristems, floral organ
primordia, and ovules. Taken together, we propose that SAP belongs to a new class of
transcription regulators essential for a number of processes in Arabidopsis flower
development.
Notes: SAP is missed in PlantTFDB.
1 SAP sequence detected in Soybean TFKB.
blast HSP result
1
SAP gene listed in PlnTFDB for Arabidopsis as well.
Last updated by Dr. Jeff Chen on Jun 3, 2009.