Cloning and sequence comparison of the mouse, human, and chicken engrailed genes reveal potential functional domains and regulatory regions

Abstract

We have isolated and characterized genomic DNA clones for the human and chicken homologues of the mouse En-1 and En-2 genes and determined the genomic structure and predicted protein sequences of both En genes in all three species. Comparison of these vertebrate En sequences with the Xenopus En-2 [Hemmati-Brivanlou et al., 1991) and invertebrate engrailed-like genes showed that the two previously identified highly conserved regions within the En protein ]reviewed in Joyner and Hanks, 1991] can be divided into five distinct subregions, designated EH1 to EH5. Sequences 5' and 3' to the predicted coding regions of the vertebrate En genes were also analyzed in an attempt to identify cis-acting DNA sequences important for the regulation of En gene expression. Considerable sequence similarity was found between the mouse and human homologues both within the putative 5' and 3' untranslated as well as 5' flanking regions. Between the mouse and Xenopus En-2 genes, shorter stretches of sequence similarity were found within the 3' untranslated region. The 5' untranslated regions of the mouse, chicken and Xenopus En-2 genes, however, showed no similarly conserved stretches. In a preliminary analysis of the expression pattern of the human En genes, En-2 protein and RNA were detected in the embryonic and adult cerebellum respectively and not in other tissues tested. These patterns are analogous to those seen in other vertebrates. Taken together these results further strengthen the suggestion that En gene function and regulation has been conserved throughout vertebrate evolution and, along with the five highly conserved regions within the En protein, raise an interesting question about the presence of conserved genetic pathways.

Two Distinct Types of Repression Domain in Engrailed: One Interacts with the Groucho Corepressor and Is Preferentially Active on Integrated Target Genes

“…We find that the EN repression function is contributed by multiple domains in both assays but that different domains have different potencies in the two systems. One conserved region (eh1 [25]) is particularly important in vivo (32) but shows very little activity in standard active repression assays involving transient transfection of cultured cells (see reference 11; confirmed in this report). This region mediates interaction with the Groucho (GRO) corepressor.…”

Retroviral Misexpression ofengrailedGenes in the Chick Optic Tectum Perturbs the Topographic Targeting of Retinal Axons

“…En-1 and En-2 are homologs of the Drosophila segment polarity genes engrailed and invected (Nusslein-Volhard and Wieschaus, 1980;Poole et al, 1985). Homologs of engrailed have been cloned at least partially and are expressed in similar patterns in zebrafish (Pattel et al, 1989;Ekker et al, 1992;Fjose et al, 1992), Xenopus (Pattel et al, 1989;Davis et al, 1991;Hemmati-Brivanlou et al, 1991), chick (Gardner et al, 1988;Pattel et al, 1989;Davis et al, 1991;Logan et al, 1992), mouse (Joyner and Martin, 1987;Logan et al, 1992), and human (Logan et al, 1992). This structural conservation among engrailed genes is underscored by the finding that the phenotype of midbrain and hindbrain structural deficits seen in En-1 knockout mice can be partially rescued by the Drosophila engrailed gene placed under the control of the mouse En-1 promoter (M. Hanks and A. Joyner, unpublished observations).…”

How many species of whipworms do we share? Whipworms from man and other primates form two phylogenetic lineages

“…To verify the possible presence of paralogs in the genome of species of Trichuris, primers according to Logan et al (1992) were used to amplify the complete sequence of the 5.8S ribosomal RNA gene (rDNA) surrounded by partial sequences of internal transcribed spacers 1 and 2. For this purpose, we have randomly chosen the isolate of Trichuris sp.…”