TY - JOUR
T1 - Micromere descendants at the blastula stage are involved in normal archenteron formation in sea urchin embryos
AU - Gurbel, Paul A.
AU - Kereiakes, Dean J.
AU - Dalesandro, Margaret R.
AU - Bahr, Raymond D.
AU - O’Connor, Christopher M.
AU - Serebruany, Victor L.
N1 - Funding Information:
Acknowledgements We are grateful to members of the Asamushi Marine Biological Station, Ushimado Marine Laboratory and the Misaki Marine Biological Station for supplying materials. This work was supported in part by Grants-in-Aid for Scientific Research (C2; No. 09839009) from the Ministry of Education, Science, Sports and Culture, Japan.
PY - 2001
Y1 - 2001
N2 - Several lines of evidence suggest that micromere signaling plays a key role in endo-mesoderm differentiation along the animal-vegetal (A-V) axis in sea urchin embryos. A recent study has suggested that the activity of micromeres of inducing endoderm differentiation of mesomere descendants is, unexpectedly, maximal at the hatching blastula stage in the echinoids Scaphechinus mirabiris and Hemicentrotus pulcherrimus. In the present study, to confirm the inductive capacity of the micromere descendants in normal development, the timing of initiation of gastrulation and the elongation rate of the archenteron were examined in both micromereless embryos and in micromereless embryos cultured until the hatching blastula stage and then recombined with micromere descendants of the same age. The micromereless embryos consistently exhibited a delay in the initiation of gastrulation and a decrease in elongation rate of the archenteron, as compared with those in controls. In contrast, when the micromereless embryos cultured until the hatching blastula stage were recombined with micromere descendants of the same age, the recombinant embryos exhibited rescue of both the delay in initiation of gastrulation and a decrease in elongation rate of the archenteron. The delayed expression of alkaline phosphatase activity, an endoderm-specific marker, in the micromereless embryos was also rescued in the recombinant embryos. The recombined micromere descendants formed the larval spicules in the same schedule as that observed in the controls. These results indicate that at the hatching blastula stage, micromere descendants emanate a signal(s) required for normal gastrulation of the presumptive endo-mesodermal region.
AB - Several lines of evidence suggest that micromere signaling plays a key role in endo-mesoderm differentiation along the animal-vegetal (A-V) axis in sea urchin embryos. A recent study has suggested that the activity of micromeres of inducing endoderm differentiation of mesomere descendants is, unexpectedly, maximal at the hatching blastula stage in the echinoids Scaphechinus mirabiris and Hemicentrotus pulcherrimus. In the present study, to confirm the inductive capacity of the micromere descendants in normal development, the timing of initiation of gastrulation and the elongation rate of the archenteron were examined in both micromereless embryos and in micromereless embryos cultured until the hatching blastula stage and then recombined with micromere descendants of the same age. The micromereless embryos consistently exhibited a delay in the initiation of gastrulation and a decrease in elongation rate of the archenteron, as compared with those in controls. In contrast, when the micromereless embryos cultured until the hatching blastula stage were recombined with micromere descendants of the same age, the recombinant embryos exhibited rescue of both the delay in initiation of gastrulation and a decrease in elongation rate of the archenteron. The delayed expression of alkaline phosphatase activity, an endoderm-specific marker, in the micromereless embryos was also rescued in the recombinant embryos. The recombined micromere descendants formed the larval spicules in the same schedule as that observed in the controls. These results indicate that at the hatching blastula stage, micromere descendants emanate a signal(s) required for normal gastrulation of the presumptive endo-mesodermal region.
KW - Cell-cell interaction
KW - Endoderm
KW - Induction
KW - Micromere
KW - Sea urchin
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U2 - 10.1007/s004270000120
DO - 10.1007/s004270000120
M3 - Article
C2 - 11455418
AN - SCOPUS:0034838957
SN - 0949-944X
VL - 211
SP - 83
EP - 88
JO - Development Genes and Evolution
JF - Development Genes and Evolution
IS - 2
ER -