Engrailed in cephalopods: a key gene related to the emergence of morphological novelties

  title={Engrailed in cephalopods: a key gene related to the emergence of morphological novelties},
  author={S{\'e}bastien Baratte and Aude Andouche and Laure Bonnaud},
  journal={Development Genes and Evolution},
The engrailed gene is a transcription factor required in numerous species for major developmental steps (neurogenesis, limb development, boundary establishment), and its evolution is known to be closely related to the evolution of the metazoan body plan. Cephalopods exhibit numerous morphological peculiarities among molluscs, such as a direct development, a complex sensory and nervous system (eyes, brain, giant axons), a reduced shell, a funnel, and a brachial crown. We assessed a potential… 

A novel role for dpp in the shaping of bivalve shells revealed in a conserved molluscan developmental program.

Expression of segment polarity genes in brachiopods supports a non-segmental ancestral role of engrailed for bilaterians

Findings suggest that bilaterians might share an ancestral, non-segmental domain of engrailed expression during early embryogenesis, and suggest the role of “segmentation genes” in organisms that lack a segmented body.

The Increased Expression of an Engrailed to Sustain Shell Formation in Response to Ocean Acidification

The results collectively suggested that the expression of Cgengrailed-1 could be triggered by CO2-driven acidification treatment, which might contribute to induce the initial shell formation in oyster larvae and the formation of periostracum in adult oyster to adapt to the acidifying marine environment.

The origins of cephalopod body plans: A geometrical and developmental basis for the evolution of vertebrate-like organ systems

The cephalopod body plans are characterized, set against those of the other bilaterians, in the light of recent data from paleontology, embryology, and molecular gene expression patterns to provide a review and new interpretation with an emphasis on the topographic transition of the soft parts that is shaped by a shared concentric circle or ovoid pattern in the embryos and adults of extant or fossil molluscs.

Eye development and photoreceptor differentiation in the cephalopod Doryteuthis pealeii

A comprehensive analysis of eye development in the squid Doryteuthis pealeii reveals conserved and convergent mechanisms underlying the evolution of complex eye formation in the Lophotrochozoa.

Possible co-option of engrailed during brachiopod and mollusc shell development

The results suggest that en and mpox are possibly involved in brachiopod embryonic shell development and the evolutionary developmental origin of lophotrochozoan biomineralization through independent gene co-option is discussed.

Cephalopod Brains: An Overview of Current Knowledge to Facilitate Comparison With Vertebrates

A critical analysis of cephalopod neural systems showing similarities to the cerebral cortex, thalamus, basal ganglia, midbrain, cerebellum, hypothalamus, brain stem, and spinal cord of vertebrates is described.

Analyses of Sox-B and Sox-E Family Genes in the Cephalopod Sepia officinalis: Revealing the Conserved and the Unusual

The data suggests that Sof-SoxB genes play similar roles in cephalopods, and appears to be involved in the early stages of vasculogenesis of the cEPhalopod closed circulatory system, a novel role for a member of this gene family.

Involvement of Hox genes in shell morphogenesis in the encapsulated development of a top shell gastropod (Gibbula varia L.)

The results suggest that Hox genes are coopted to various functions in molluscs, which suggest that the molecular mechanisms underlying shell synthesis may consist of numerous conserved pattern-formation genes.



Molluscan engrailed expression, serial organization, and shell evolution

In situ hybridization and antibody studies show iterated engrailed‐gene expression in transverse rows of ectodermal cells bounding plate field development and spicule formation in the chiton, Lepidochitona caverna, as well as in cells surrounding the valves and in the early development of the shell hinge in the clam, Transennella tantilla.

Expression of engrailed proteins in arthropods, annelids, and chordates.

Expression of Patella vulgata orthologs of engrailed and dpp-BMP2/4 in adjacent domains during molluscan shell development suggests a conserved compartment boundary mechanism.

It is concluded that engrailed and dpp are most likely involved in setting up a compartment boundary between these cells, very similar to the situation in, for example, the developing wing imaginal disc in Drosophila.

Embryonic expression of engrailed in sea urchins.

The evolution of engrailed genes after duplication and speciation events

  • J. Gibert
  • Biology
    Development Genes and Evolution
  • 2002
The Duplication-Degenerescence-Complementation model recently proposed by Force et al. seems to be the main process involved in functional diversification after duplication events, and selection seems to maintain a certain redundancy between engrailed paralogues.

Sequence and embryonic expression of the amphioxus engrailed gene (AmphiEn): the metameric pattern of transcription resembles that of its segment-polarity homolog in Drosophila.

The segmental expression of AmphiEn in forming somites suggests that the functions of engrailed homologs in establishing and maintaining a metameric body plan may have arisen only once during animal evolution.

Radical alterations in the roles of homeobox genes during echinoderm evolution

The expression domains in echinoderms of three important developmental regulatory genes ( distal-less, engrailed and orthodenticle ), all of which encode transcription factors that contain a homeodomain are reported, demonstrating the evolutionary lability of regulatory genes that are widely viewed as conservative.

Evolution of distinct expression patterns for engrailed paralogues in higher crustaceans (Malacostraca)

Phylogenetic analysis of en sequences from crustacean and insects suggests that the two en genes from the apterygote insect Thermobia domestica may be related to en1 and en2 of higher crustaceans.

Growth and patterning from the engrailed interface.

  • A. Hidalgo
  • Biology
    The International journal of developmental biology
  • 1998
Arguments are presented here to support the notion that the compartment boundary is a consequence of decapentaplegic function in the control of growth, and regulatory interactions between en/En-1 and hh/Shh may be significant in the context of morphogenetic regulation during normal development.

The spatial and temporal expression of Ch-en, the engrailed gene in the polychaete Chaetopterus, does not support a role in body axis segmentation.

Characterizing the expression pattern of the segment polarity gene engrailed (en) in a basal annelid, the polychaete Chaetopterus, shows that Ch-en is expressed throughout larval life in a complex spatial and temporal pattern and Genomic Southern blotting suggests that this is the only en class gene in this animal.