The Tousled gene in A. thaliana encodes a protein kinase homolog that is required for leaf and flower development.

Mutation at the TOUSLED locus of A. thaliana results in a complex phenotype, the most dramatic aspect of which being the abnormal flowers produced in mutant plants. tsl flowers show a random loss of floral organs, and organ development is impaired. The TSL gene appears to be required in the floral meristem for correct initiation of floral organ primordia and for proper development of organ primordia. Loss of TSL function also affects flowering time and leaf morphology. Using a mutation derived by T-DNA insertion mutagenesis, we have cloned the TSL gene and found that it encodes a protein kinase homolog with a novel N-terminal domain. This protein kinase gene identifies a novel signaling/regulatory pathway used during development in Arabidopsis.