Tg(Afp-GFP) expression marks primitive and definitive endoderm lineages during mouse development.

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• Alpha-fetoprotein (Afp) is a key serum protein during embryonic development.
• Afp is produced by various endodermal tissues, including the fetal liver and gut.

Purpose of the Study:

• To investigate the utility of Afp gene regulatory elements for driving reporter gene expression in endodermal tissues.
• To generate transgenic mouse models for visualizing and isolating endodermal cell lineages.

Main Methods:

• Generation of transgenic mouse lines (Tg(Afp-GFP)) utilizing the Afp promoter/enhancer to drive green fluorescent protein (GFP) expression.
• Real-time visualization of GFP fluorescence in various embryonic tissues.
• Comparison of GFP localization with endogenous Afp transcripts and protein.
• Flow cytometric analysis of fetal liver hepatocytes.

Main Results:

• Bright GFP fluorescence accurately reflected Afp expression patterns in visceral endoderm, yolk sac endoderm, gut, and pancreas.
• Transgene expression was observed in most Afp-expressing embryonic cells but a subset of fetal liver cells.
• The Tg(Afp-GFP) mice enabled effective flow cytometry of fetal liver hepatocytes.

Conclusions:

• The Afp promoter/enhancer elements are effective for directing gene expression in specific endodermal lineages.
• Tg(Afp-GFP) mice are a valuable tool for live imaging, identification, quantitation, and isolation of primitive and definitive endoderm cells.
• This model system facilitates research into endoderm development and cell biology.