Complexity and Conservation of Thermospermine-Responsive uORFs of SAC51 Family Genes in Angiosperms.

ABSTRACT: ACAULIS5 (ACL5) encodes thermospermine synthase in Arabidopsis and its loss-of-function mutant acl5 shows excess xylem differentiation and severe dwarfism. SAC51 encodes a basic helix-loop-helix (bHLH) protein and was identified from sac51-d, a dominant suppressor mutant of acl5, which restores the wild-type phenotype without thermospermine. The 5' leader of the SAC51 mRNA contains multiple upstream open-reading frames (uORFs) and sac51-d has a premature stop codon in the fourth uORF. This uORF is conserved among SAC51 family genes in vascular plants. According to the GUS reporter assay, the SAC51 promoter was not responsive to thermospermine but the SAC51 5' leader fused to the constitutive 35S promoter enhanced the GUS activity in response to thermospermine. Disruption experiments of eac

SUBMITTER: Ishitsuka S 

PROVIDER: S-EPMC6504692 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature