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

@article{Baratte2007EngrailedIC,
  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},
  year={2007},
  volume={217},
  pages={353-362}
}
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… 

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References

SHOWING 1-10 OF 40 REFERENCES

Molluscan engrailed expression, serial organization, and shell evolution

TLDR
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.

TLDR
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
TLDR
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.

TLDR
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

TLDR
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)

TLDR
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
TLDR
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.

TLDR
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.