Plants contain b-amylase-like proteins (BAMs; enzymes usually associated with starch breakdown) present in the nucleus rather than targeted to the chloroplast. They possess BRASSINAZOLE RESISTANT1 ( @entity16046 )-type DNA binding domains--also found in transcription factors mediating brassinosteroid (BR) responses. The two @entity958 @entity16046 -BAM proteins ( @entity70314 and @entity70315 ) bind a cis-regulatory element that both contains a G box and resembles a BR-responsive element. In protoplast transactivation assays, these @entity16046 -BAMs activate gene expression. Structural modeling suggests that the BAM domain's glucan binding cleft is intact, but the recombinant proteins are at least 1000 times less active than chloroplastic b-amylases. Deregulation of @entity16046 -BAMs (the bam7bam8 double mutant and @entity70315 -overexpressing plants) causes altered leaf growth and development. Of the genes upregulated in plants overexpressing @entity70315 and downregulated in bam7bam8 plants, many carry the cis-regulatory element in their promoters. Many genes that respond to @entity4375 are inversely regulated by @entity16046 -BAMs. We propose a role for @entity16046 -BAMs in controlling plant growth and development through crosstalk with BR signaling. Furthermore, we speculate that @entity16046 -BAMs may transmit metabolic signals by binding a ligand in their BAM domain, although diurnal changes in the concentration of @entity7969 , a candidate ligand produced by chloroplastic b-amylases, do not influence their transcription factor function.

b-amylase-like proteins function as transcription factors in XXXX , controlling shoot growth and development.

@entity7969 :: ('MESH:D008320', 'Chemical') :: ['maltose'] @entity958 :: ('3702', 'Species') :: ['Arabidopsis thaliana'] @entity70314 :: ('819196(Tax:3702)', 'Gene') :: ['BAM7'] @entity4375 :: ('11246', 'Species') :: ['BRs'] @entity16046 :: ('843845(Tax:3702)', 'Gene') :: ['BZR1'] @entity70315 :: ('834566(Tax:3702)', 'Gene') :: ['BAM8']
@entity958 :: (3702,Species) :: ['Arabidopsis']
