The lateral organ boundaries (LOB) gene encodes a plant-specific protein of unknown function that is expressed at the adaxial base of initiating lateral organs. The N-terminal of the LOB protein contains an approximately 100-amino acid conserved domain (the LOB domain) that is present in 42 other Arabidopsis thaliana proteins as well as in proteins from a variety of other plant species. The LOB domain contains conserved blocks of amino acids that identify the LOB domain (LBD) gene family. In particular, a conserved C-x(2)-C-x(6)-C-x(3)-C motif, which is the defining feature of the LOB domain, is present in all LBD proteins [1].

1: The lateral organ boundaries gene defines a novel, plant-specific gene family. Shuai B, Reynaga-Pena CG, Springer PS; Plant Physiol. 2002;129:747-761. PMID:12068116