Taxonomic distribution of proteins containing KNOX1 domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing KNOX1 domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Functional analysis of the conserved domains of a rice KNOX homeodomain protein, OSH15.

Nagasaki H, Sakamoto T, Sato Y, Matsuoka M
Plant Cell. 2001; 13: 2085-98

The rice KNOX protein OSH15 consists of four conserved domains: the MEINOXdomain, which can be divided into two subdomains (KNOX1 and KNOX2); the GSEdomain; the ELK domain; and the homeodomain (HD). To investigate the function of each domain, we generated 10 truncated proteins with deletions in the conserveddomains and four proteins with mutations in the conserved amino acids in the HD. Transgenic analysis suggested that KNOX2 and HD are essential for inducing theabnormal phenotype and that the KNOX1 and ELK domains affect phenotype severity. We also found that both KNOX2 and HD are necessary for homodimerization and that only HD is needed for binding of OSH15 to its target sequence. Transactivationstudies suggested that both the KNOX1 and ELK domains play a role in suppressing target gene expression. On the basis of these findings, we propose thatoverproduced OSH15 probably acts as a dimer and may ectopically suppress theexpression of target genes that induce abnormal morphology in transgenic plants.