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#trophoblast

2 public questions tagged with this topic.

Fertilization in mammals-ll

Trophoblast primarily contributes to:

Trophectoderm is outer epithelial layer of blastocyst specified when outer polar cells suppress Hippo kinases, allowing nuclear YAP and induction of Cdx2 transcription factor. This lineage does not contribute to fetus itself but differentiates into cytotrophoblast and syncytiotrophoblast that invade decidua, secrete human chorionic gonadotropin, and build chorionic villi of placenta. It establishes fetomaternal exchange interface providing nutrition, gas exchange, endocrine support and immune protection. Trophoblast commitment therefore underlies implantation, placental development essential f

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 12: Trophoblast differentiation and placental lineage specification via Cdx2.

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Fertilization in mammals-lll

Blastocyst cells forming extraembryonic structures:

Blastocyst differentiation yields two lineages: inner cell mass pluripotent and outer trophoblast. Trophoblast cells after compaction express Cdx2 driven by nuclear YAP-TEAD activity where Hippo pathway inactive. These cells proliferate to form cytotrophoblast and syncytiotrophoblast contributing to placenta, chorion, and implantation invasion secreting hCG and facilitating uterine interface. Inner cell mass generates embryo proper, not extraembryonic placenta. Polar bodies degenerate, zona pellucida is extracellular coat shed before implantation. Therefore trophoblast represents exclusive pro

Ref: Posfai et al., Dev Biol 2021: Trophectoderm lineage specification and placental derivatives of blastocyst.

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