title: Identification of a novel mouse Iroquois homeobox gene, Irx5, and chromosomal localisation of all members of the mouse Iroquois gene family.
abstract: The Drosophila genes of the Iroquois-Complex encode homeodomain containing transcription factors that positively regulate the activity of certain proneural Achaete/Scute-C (AS-C) genes during the formation of external sensory organs (J. L. Gomez-Skarmeta and J. Modolell, EMBO J 17:181-190, 1996). Previously, we have identified three highly-related genes of the mouse Iroquois gene family that exert specific expression patterns in the central nervous system (A. Bosse et al., Mech Dev 69:169-181, 1997). In the present paper, we report the identification of a novel member of the Iroquois gene family, Irx5, that shows a restricted spatio/temporal expression during early mouse embryogenesis, distinct from the expression of Irx1-3. An extensive sequence analysis of 20 Iroquois-like genes from seven organisms reveals a high conservation of the homeodomain. Phylogenetic tree reconstruction showed a clustering of the members of the Iroquois gene family into groups of orthologous genes. Together, with the data obtained from the chromosomal mapping analysis, the results indicate that these genes have appeared in vertebrates during evolution as a result of gene duplication.
authors.affiliation: Department of Molecular Cell Biology, Max Planck Institute of Biophysical Chemistry, Göttingen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Bosse
authors.forename: A
authors.initials: A
authors.lastname: Stoykova
authors.forename: K
authors.initials: K
authors.lastname: Nieselt-Struwe
authors.forename: K
authors.initials: K
authors.lastname: Chowdhury
authors.forename: N G
authors.initials: NG
authors.lastname: Copeland
authors.forename: N A
authors.initials: NA
authors.lastname: Jenkins
authors.forename: P
authors.initials: P
authors.lastname: Gruss
mesh_terms: D000818:Animals; D001483:Base Sequence; D002642:Chick Embryo; D002874:Chromosome Mapping; D005314:Embryonic and Fetal Development / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009420:Nervous System / Q000196:embryology*; D012333:RNA, Messenger / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D018398:Homeodomain Proteins; C501591:IRX1 protein, human; C501600:IRX5 protein, human; C501592:Irx1 protein, mouse; C501601:Irx5 protein, mouse; D012333:RNA, Messenger; D014157:Transcription Factors