Open AccessStructure of homeobox-leucine zipper genes suggests a model for the evolution of gene families.
Author(s) -
Mark Schena,
Ronald W. Davis
Publication year - 1994
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.91.18.8393
Subject(s) - homeobox , leucine zipper , biology , emx2 , homeobox a1 , genetics , homeobox protein nkx 2.5 , gene , hnf1b , zipper , atf3 , basic helix loop helix leucine zipper transcription factors , gene duplication , gene family , transcription factor , dna binding protein , gene expression , promoter , algorithm , computer science
Homeobox genes are present in both plants and animals. Homeobox-leucine zipper genes, however, have been identified thus far only in the small mustard plant Arabidopsis thaliana. This observation suggests that homeobox-leucine zipper genes evolved after the divergence of plants and animals, perhaps to mediate specific regulatory events. To better understand this gene family, we isolated several sequences containing the homeobox-leucine zipper motif and carried out a comparative analysis of nine homeobox-leucine zipper genes (HAT1, HAT2, HAT3, HAT4, HAT5, HAT7, HAT9, HAT14, and HAT22). Gene structures, sequence comparisons, and chromosomal locations suggest a simple model for the evolution of these genes. The model postulates that a primordial homeobox gene acquired a leucine zipper by exon capture. The nascent homeobox-leucine zipper gene then appears to have undergone a series of gene duplication and chromosomal translocation events, leading to the formation of the HAT gene family. This work has general implications for the evolution of regulatory genes.