FoxA expression pattern in two polychaete species, Alitta virens and Platynereis dumerilii: Examination of the conserved key regulator of the gut development from cleavage through larval life, postlarval growth, and regeneration

Abstract

Background foxA orthologs are involved in various processes from embryo patterning to regulation of metabolism. Since foxA conserved role in the development of the gut of errant annelids has never been thoroughly studied, we used a candidate gene approach to unravel the molecular profile of the alimentary canal in two closely related nereid worms with a trochophore‐type lecithotrophic larva. Results The character of foxA expression in the two polychaetes was similar but not identical. The genes were successively activated first in blastoporal cells, then in the stomodeum, the midgut, and hindgut primordia, and in the cells of central and peripheral nervous system. Before the start of active feeding of nectochaetes, we observed a short phase of foxA expression in the entire digestive tract. After amputation of posterior segments, foxA expression was established de novo in the new terminal part of the intestine, and then in the developing hindgut and the anus. Conclusions We discovered an early marker of endoderm formation previously unknown in errant annelids. Its expression dynamics provided valuable insights into the gut development. Comparative analysis of foxA activity suggests its primary role in gastrulation morphogenesis independently of its type and in midgut and foregut specification. Developmental Dynamics 248:728–743, 2019. © 2018 Wiley Periodicals, Inc.

Comparative Aspects of Annelid Regeneration: Towards Understanding the Mechanisms of Regeneration

“…In this type of healing, the severed gut edges also fuse, and a blind gut end forms [10,12]. In some cases of posterior regeneration, the severed edges of the epidermis and the gut epithelium fuse directly with each other and restore the anus by the wound healing process ("open regeneration" in nereids [34]).…”

“…The wound epithelium is formed by the rearrangement of epithelial cells, but not by their active proliferation [36][37][38][39]. Transition to the next stage of regeneration, the blastema formation, is characterized by a sharp upregulation of cell proliferation and several genes known to be important developmental regulators [12,34,39]. After anterior and usually after posterior amputation, the wound heals by fusion of the severed edges of the epidermis over it.…”

Neurons and Glia Cells in Marine Invertebrates: An Update

“…Regeneration has been studied mainly in Nereis virens (Holmes, 1931), Nereis diversicolor (Clark and Bonney, 1960), Owenia fusiformis (Coulon et al, 1989), Eurythoe complanata (Zapata-Vívenes, 2005), Dorvillea bermudensis (Paulus and Müller, 2006), Cirratulus cf. cirratus (Weidhase et al, 2014), Typosyllis antoni (Weidhase et al, 2017), Alitta virens (Kozin et al, 2017), and in P. dumerilii (Kostyuchenko et al, 2019). Collectively, these studies demonstrated that each specie present differences in its ability to regenerate.…”

Structural and Functional Characterization of the FGF Signaling Pathway in Regeneration of the Polychaete Worm Alitta virens (Annelida, Errantia)

“…One of the best developed models of segment recovery are nereid polychaetes, such as Alitta ( Nereis ), Platynereis and Perinereis . Their regeneration is predominantly epimorphic, with some substantial signs of morphallaxis [ 1 , 2 ].…”