Isolation and expression of Pax6 and atonal homologues in the American horseshoe crab, Limulus polyphemus

Abstract

Pax6 regulates eye development in many animals. In addition, Pax6 activates atonal transcription factors in both invertebrate and vertebrate eyes. Here, we investigate the roles of Pax6 and atonal during embryonic development of Limulus polyphemus rudimentary lateral, medial and ventral eyes, and the initiation of lateral ommatidial eye and medial ocelli formation. Limulus eye development is of particular interest because these animals hold a unique position in arthropod phylogeny and possess multiple eye types. Furthermore, the molecular underpinnings of eye development have yet to be investigated in chelicerates. We characterized a Limulus Pax6 gene, with multiple splice products and predicted protein isoforms, and one atonal homologue. Unexpectedly, neither gene is expressed in the developing eye types examined, although both genes are present in the lateral sense organ, a structure of unknown function.

Molecular regionalization in the compact brain of the meiofaunal annelid Dinophilus gyrociliatus (Dinophilidae)

“…8a–c). This supports previous findings about six3 / 6 playing a major role in demarcating the anterior or anteromedian region of the brain in several invertebrate groups [22, 34, 77], and especially in patterning the larval apical organ and cerebral ganglia in the annelids C. teleta and P. dumerilii (Fig. 8d, e, [23]).…”

Chelicerata

“…This has allowed researchers access to the embryos of these animals and their development has been described in some detail, as well as studied through embryonic manipulations (Kingsley 1892 ;Kishinouye 1893 ;Iwanoff 1933 ;Sekiguchi 1979 , 1980 ;Sekiguchi et al 1982 ;Itow 1990Itow , 2005Itow et al 1991 ). Furthermore, there is a growing number of studies that have examined gene or protein expression during horseshoe crab embryogenesis and other aspects of development that have provided some valuable insights into evolutionary developmental biology (Popadic and Nagy 2001 ;Damen et al 2002 ;Mittmann 2002 ;Blackburn et al 2008 ). In addition, the recent sequencing of the genome of Limulus polyphemus (Table 5.1 ; Nossa et al 2014 ) is anticipated to fuel further studies of gene expression in this species.…”

De novo transcriptome of the European brittle star Amphiura filiformis pluteus larvae

“…The tree was constructed using trimmed sequences mainly limited to the conserved paired domains and homeodomain of the protein based on (Omori et al, 2011) (see also (Blackburn et al, 2008)). Phylogenies were constructed using Maximum likelihood (PHYML tool, by default LG substitution model, (Le and Gascuel, 2008)), Parsimony and Distance analyses using SeaView 4.2.12 software (Gouy et al, 2010;Guindon and Gascuel, 2003;Guindon et al, 2009).…”