Disease relevance of ACL5

• Because these mutants do not rescue the dwarfism of known phytohormone-related mutants, the SAC genes appear to act specifically on the ACL5 pathways [1].
• Expression of the recombinant ACL5 protein in Escherichia coli showed that ACL5 possesses spermine synthase activity [2].

High impact information on ACL5

• We also found that expression of the ACL5 cDNA under the control of a heat shock gene promoter in acl5 mutant plants restores the phenotype in a heat shock-dependent manner [2].
• We propose that ACL5/TKV is involved in vein definition (defining the boundaries between veins and nonvein regions) and in polar auxin transport, and that polyamines are involved in this process [3].
• Here we addressed a specific role of spermine during high salt stress using an Arabidopsis double knockout-mutant plant (acl5/spms) which cannot produce spermine [4].
• Three cDNAs with high homology to spermine (Spm) synthases in Arabidopsis were isolated from apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.]. MdACL5-1 and MdACL5-2 have high homology with ACL5 and MdSPMS has high homology with AtSPMS [5].
• The genome of Arabidopsis thaliana has two genes encoding spermine synthase: ACAULIS5 (ACL5), whose loss-of-function mutants show a severe defect in stem elongation, and SPMS [6].

Biological context of ACL5

• The Arabidopsis genome contains four genes that encode proteins similar to both spermidine synthase and spermine synthase of other organisms [7].

References