Diverse sets of developmental programs including cytoskeleton organization, cell lineage specification, muscle and neuron differentiation, limb and eye formation, imaginal disk development are controlled by LIM-homeobox genes encoding LIM-homeodomain (LIM-HD) transcription factors. LIM-domains are known as adaptors and functional modifiers of the protein-protein interactions and of the specific contacts between the members of functional complexes mediating activation of some constitutive proteins. Primary structure of LIM-HD proteins is remarkably evolutionary conserved in vertebrates and invertebrates. Though the genome size of Drosophila is about 5 % of the mammal genome the majority of its gene families and signaling pathways are similar to those of the mammals. There are some well known LIM-domain-containing proteins in Drosophila: Arrowhead, Apterous, Islet, dLim and Lim3 transcription factors; DLMO and Prickle proteins, as well as Chip, RLIM, Ssdp cofactors that modulate the LIM-HD function. Drosophila is a unique model system to analyze genetic interactions and transcription complexes in vivo. Genetic and molecular approaches including isolation of extragenic supressors of mutations in LIM-HD proteins may be used for identification of target genes which interact directly with LIM-HD proteins and that are necessary for specification of cell identity.
Keywords:
