Blastomeres derived from the vegetal pole provide extra-embryonic nutrition to sturgeon (Acipenser) embryos: Transition from holoblastic to meroblastic cleavage

0556615 - BTÚ 2023 RIV NL eng J - Journal Article
Shah, M. - Fatira, E. - Iegorova, Viktoriia - Xie, X. - Gela, D. - Rodina, M. - Franek, M. - Pšenička, M. - Saito, T.
Blastomeres derived from the vegetal pole provide extra-embryonic nutrition to sturgeon (Acipenser) embryos: Transition from holoblastic to meroblastic cleavage.
Aquaculture. Roč. 551, MAR 30 2022 (2022), č. článku 737899. ISSN 0044-8486. E-ISSN 1873-5622
R&D Projects: GA ČR(CZ) GA20-23836S
Institutional support: RVO:86652036
Keywords : yolk syncytial layer * morphogenetic movements * gene-expression * holostean fish * germ
OECD category: Marine biology, freshwater biology, limnology
Impact factor: 4.5, year: 2022
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S0044848622000138?via%3Dihub

Generally, holoblastic cleavage in embryos (as in amphibians) in which all blastomeres contribute to one of the germ layers, are preserved as a stem lineage of vertebrates, and meroblastic cleavage has evolved independently in each vertebrate lineage. The increasing egg size: yolk volume is the key factor for transition from holoblastic to meroblastic cleavage patterns. Sturgeon (Acipenser) eggs are two times larger than those of the African clawed frog Xenopus laevis (amphibian), despite the varying size, sturgeon embryos retain nearly the same developmental characteristics as X. laevis. Comparatively, the fate of blastomeres derived from the vegetal pole (VP) of a sturgeon embryo is unspecified. Thus, the goal of this study was to determine whether the VP of the embryo contributes to embryonic development, or is simply extra-embryonic. This may also reveal whether the transition of the cleavage pattern (holoblastic to meroblastic) in the actinopterygian lineage is correlated with the egg size: yolk volume. Here, we found that sturgeon vegetal blastomeres formed only primordial germ cells, and the rest were made up of cellular yolk (yolk cells, YCs). Morphological and phenotypic characteristics revealed that after the 1 k-cell / mid-blastula transition, YCs became transcriptionally inactive and served only to provide nutrition to larvae as they developed. Furthermore, inhibition of vegetal blastomeres revealed that sturgeon can utilize their yolk in an acellular form, similar to teleosts, implying that meroblastic cleavage in the actinopterygians, like teleosts, might have evolved by the fusion of the vegetal blastomeres.
Permanent Link: https://hdl.handle.net/11104/0340743