Nhlrc2 is crucial during mouse gastrulation.

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• NHL repeat containing 2 (Nhlrc2) is essential for mammalian development, but its precise role and the timing of lethality in its absence are not fully understood.
• Previous studies indicate that Nhlrc2 loss leads to embryonic lethality, necessitating a detailed examination of its function during early embryogenesis.

Purpose of the Study:

• To determine the exact timing of embryonic lethality in Nhlrc2 knockout (KO) mice.
• To investigate the in situ expression pattern of Nhlrc2 during the critical period of early postimplantation development.

Main Methods:

• Generation and analysis of Nhlrc2 knockout mouse embryos using CRISPR/Cas9 technology.
• In vitro fertilization and embryo culture to assess preimplantation development.
• LacZ reporter gene expression analysis to map Nhlrc2 expression patterns.
• Genotyping and morphological assessment of embryos at various developmental stages (E6.5, E7.5, E8.5).

Main Results:

• Nhlrc2 KO preimplantation embryos and derived embryonic stem cells developed normally.
• Postimplantation Nhlrc2 KO embryos showed normal development until embryonic day 6.5.
• Developmental arrest occurred by embryonic day 7.5, with significant lethality by E8.5.
• Nhlrc2 expression was widespread, with highest levels in epiblast/ectoderm and extraembryonic ectoderm on E6.5-E7.5.
• KO embryos exhibited failed gastrulation and amniotic folding, remaining at the cylinder stage.

Conclusions:

• NHLRC2 is indispensable for successful early postimplantation development in mice.
• Loss of NHLRC2 function disrupts critical developmental processes including gastrulation and amniotic fold formation.
• Further research into the evolutionarily conserved NHLRC2 will elucidate molecular pathways governing early mammalian development.