SHOOTMERISTEMLESS (STM) encodes a member of the class I KNOX homeodomain protein family that is required for meristem development and maintenance. We have isolated both genomic and cDNA clones of STM from the perennial weed leafy spurge. A comparison to other class I KNOX genes indicates that EeSTM represents an orthologue of AtSTM and not one of the other class I KNOX gene family members. 5′ rapid amplification of cDNA ends (RACE) indicated that the transcription initiation site is close to the start of translation and is conserved between arabidopsis and leafy spurge. Putative cis-acting elements were identified in the EeSTM promoter, including a tuber-specific sucrose-responsive element, which could play a major role in the expression of EeSTM in root tissue.
Nomenclature: Arabidopsis, Arabidopsis thaliana L. ARATH; leafy spurge, Euphorbia esula L. EPHES.