TY - JOUR
T1 - The involvement of engrailed and wingless during segmentation in the onychophoran Euperipatoides kanangrensis (Peripatopsidae:Onychophora) (Reid 1996)
AU - Eriksson, Bo Joakim
AU - Tait, Noel N.
AU - Budd, Graham E.
AU - Akam, Michael
PY - 2009
Y1 - 2009
N2 - As the putative sister group to the arthropods, onychophorans can provide insight into ancestral developmental mechanisms in the panarthropod clade. Here, we examine the expression during segmentation of orthologues of wingless (Wnt1) and engrailed, two genes that play a key role in defining segment boundaries in Drosophila and that appear to play a role in segmentation in many other arthropods. Both are expressed in segmentally reiterated stripes in all forming segments except the first (brain) segment, which only shows an engrailed stripe. Engrailed is expressed before segments are morphologically visible and is expressed in both mesoderm and ectoderm. Segmental wingless expression is not detectable until after mesodermal somites are clearly distinct. Early engrailed expression lies in and extends to both sides of the furrow that first demarcates segments in the ectoderm, but is largely restricted to the posterior part of somites. Wingless expression lies immediately anterior to engrailed expression, as it does in many arthropods, but there is no precise cellular boundary between the two expression domains analogous to the overt parasegment boundary seen in Drosophila. Engrailed stripes extend along the posterior part of each limb bud, including the antenna, while wingless is restricted to the distal tip of the limbs and the neurectoderm basal to the limbs.
AB - As the putative sister group to the arthropods, onychophorans can provide insight into ancestral developmental mechanisms in the panarthropod clade. Here, we examine the expression during segmentation of orthologues of wingless (Wnt1) and engrailed, two genes that play a key role in defining segment boundaries in Drosophila and that appear to play a role in segmentation in many other arthropods. Both are expressed in segmentally reiterated stripes in all forming segments except the first (brain) segment, which only shows an engrailed stripe. Engrailed is expressed before segments are morphologically visible and is expressed in both mesoderm and ectoderm. Segmental wingless expression is not detectable until after mesodermal somites are clearly distinct. Early engrailed expression lies in and extends to both sides of the furrow that first demarcates segments in the ectoderm, but is largely restricted to the posterior part of somites. Wingless expression lies immediately anterior to engrailed expression, as it does in many arthropods, but there is no precise cellular boundary between the two expression domains analogous to the overt parasegment boundary seen in Drosophila. Engrailed stripes extend along the posterior part of each limb bud, including the antenna, while wingless is restricted to the distal tip of the limbs and the neurectoderm basal to the limbs.
UR - http://www.scopus.com/inward/record.url?scp=67349239694&partnerID=8YFLogxK
U2 - 10.1007/s00427-009-0287-7
DO - 10.1007/s00427-009-0287-7
M3 - Article
C2 - 19434423
AN - SCOPUS:67349239694
SN - 0949-944X
VL - 219
SP - 249
EP - 264
JO - Development Genes and Evolution
JF - Development Genes and Evolution
IS - 5
ER -