UNSW Embryology
Molecular Development- Engrailed 1	Embryology Home Page
Page
Page LinksIntroduction ReferencesAbout Notes Other pages: | Molecular Development | Signaling | Axes Development | Neural Axes | Limb Axes |	Back to Molecular Development
Introduction Engrailed genes are a family of transcription factors that are differentially expressed within the limb buds of the embryo. Belongs to the Homeobox family of transcription factors that bind DNA and can activate or inhibit new gene expression. These notes still under development.
From Flybase (open Flybase Entry) D. melanogaster gene engrailed , abbreviated as en , encodes a product with the function specific RNA polymerase II transcription factor which is localised to the nucleus it is expressed in the embryo (antennal segment , central nervous system , epidermis , female genital disc and 12 other listed tissues) and larva (dorsal mesothoracic disc , dorsal metathoracic disc and ventral thoracic disc ) It has a known homologue in Homo sapiens , Mus , Caenorhabditis elegans , Drosophila sp. and Mus musculus. It has been sequenced and its amino acid sequence contains a 'Homeobox' domain signature , a 'Homeobox' engrailed-type protein signature and a 'Homeobox' domain profile. It has been mapped by recombination to 2-62.0 and cytologically to 48A3 . It interacts genetically with cg , ci , rho , ftz , dpp , inv , nub , ph-d , ph-p and hh. There are 105 recorded mutant alleles , of which at least 12 are available from the public stock centers. Amorphic mutations have been isolated which affect the embryonic cuticle , the embryonic apodeme , the embryonic somatic muscle and 4 other listed tissues and are embryonic recessive lethal and recessive visible. en is discussed in 853 published references , dated between 1929 and 1999. These include at least 125 studies of mutant phenotypes , 10 studies of wild-type function and 16 molecular studies . Among findings on en function, cell affinities in the adult abdomen depend on en : cells of the P compartment have affinities that are distinct from A cells.
References Hidalgo A Growth and patterning from the engrailed interface. Int J Dev Biol 1998;42(3 Spec No):317-24 The Drosophila wing is divided into anterior and posterior compartments, the latter characterized by the expression of the engrailed gene. A comparative analysis is presented here, and suggests that a primary conserved role of engrailed is to drive growth of limbs along the proximo-distal axis. The Apical Ectodermal Ridge in vertebrate limbs resembles the Antero/ Posterior compartment boundary in fly wings, particularly in molecular aspects. Multiple evidence suggests that the fly wing Antero/Posterior boundary is not the result of differential cell affinities between all anterior and posterior cells, but responds to the area of cell communication between anterior and posterior compartments. Arguments are presented here to support the notion that the compartment boundary is a consequence of decapentaplegic function in the control of growth. Patterning, on the other hand, requires the participation of several genes, among which are engrailed, invected and hedgehog. Finally, regulatory interactions between en/En-1 and hh/Shh may be significant in the context of morphogenetic regulation during normal development. Joyner AL Engrailed, Wnt and Pax genes regulate midbrain--hindbrain development. Trends Genet 1996 Jan;12(1):15-20 The mouse Engrailed, Wnt and Pax genes, which are homologues of Drosophila segmentation genes, have provided a critical genetic entry point for dissecting the molecular and cellular control of mesencephalon and metencephalon development in vertebrates. Mutant phenotypes and gene expression data suggest that six members of these gene families are required for early formation of these brain regions. Ectopic transplantation studies have shown that the midbrain-hindbrain-junction protein can act as an organizer and recruit certain host cells to re-establish parts of the entire region. Taken together, these studies indicate that the mesencephalon and metencephalon develop as one independent unit, and that the genetic network regulating development of this region involves conserved genes that control segmentation in Drosophila. By analogy, segmentation of the rest of the brain might best be described in terms of 'genetic units' defined by genetic and transplantation data. References from PubMed (requires internet connection to open links)
Database Entry Links Genbank | Swiss-protein Human Genbank Entries   Help Locus Link Help Page Link code PubMed OMIM RefSeq GenBank UniGene Variation top of page Swiss-Protein NiceProt View HOMEOBOX PROTEIN ENGRAILED-1 found in SWISS-PROT: 40
Lecture Notes Please note that these notes only relate to the Anat 3311 Course. This section is not completely available, as I have been unable to transfer all my Lecture notes and research material in time for the deadline. This will be available in later versions. Early Development Lecture Simple pictures illustrating the early events of fertilization. Spinal Cord Development Figures and text relating to early events of spinal cord formation. Sex Determination Text relating to the molecular events of sex determination in the embryo. Polarity Concepts A short comparison of establishing positional information in embryos. Antennapedia The fly mutation that opened the field of Hox Genes and the conservation of pattern formation control mechanisms between species in embryonic development.
External WWW Search This current page has additional windows that allow searching of OMIM Morbid Map and OMIM Gene Map and access to other External WWW Search pages (Medical dictionaries, glossaries, chemicals and drugs). In the DNA Notes there is a window to search the Human Genome by keyword and also to search for a specific species classification. In the DNA Notes there is also a page with 3 search windows for Nucleotide Sequence, Protein Sequence and Biomolecule 3D Structure from NCBI. In the Chemical Notes there is a window to search a Material Safety Data Sheet database for a specific chemical and its associated hazard.
About Notes Notes from the Embryology Program compiled and written by Dr Mark Hill. This updated section of notes is still being developed Mar2000 and is not yet complete. Note that reference lists are only relevant to the date of the original search.	Links Serial Sections Homepage Human Homepage Pig Homepage
m.hill@unsw.edu.au Date Last Modified: 19/3/99 This site maintained by Dr M. Hill