Gene trap screening using negative selection: identification of two tandem, differentially expressed loci with...

Area of Science:

• Developmental Biology
• Hematopoiesis
• Gene Regulation

Background:

• Gene trap screens are effective for identifying novel genes involved in cellular differentiation.
• The galtek fusion gene enables both expression detection and cell ablation for functional studies.
• Understanding hematopoietic gene regulation is crucial for developmental biology and disease research.

Purpose of the Study:

• To identify novel hematopoietic loci in mouse embryonic stem cells using a gene trap approach.
• To characterize the function and expression patterns of newly identified genes.
• To investigate the role of these genes in early hematopoietic development.

Main Methods:

• Construction and application of a galtek gene trap in mouse embryonic stem cells.
• In vitro differentiation of gene-trapped ES cell clones with FIAU selection.
• Cloning and characterization of endogenous transcribed sequences from gene trap insertion sites.
• Northern blot and whole-mount in situ hybridization to assess gene expression patterns.

Main Results:

• A gene trap screen identified one clone (F3) with FIAU-sensitive erythropoiesis.
• Two novel, unrelated transcription units (F3-1 and F3-2) were identified at the F3 insertion site.
• F3-2 expression was detected in embryonic tissues, including the aortic endothelium, overlapping with gata-2 expression.
• FIAU sensitivity suggests galtek expression during early hematopoietic cell formation.

Conclusions:

• The F3 clone harbors novel genes (F3-1, F3-2) potentially regulating early hematopoietic development.
• F3-2 expression in the aorta suggests a role in endothelial and hematopoietic precursor development.
• The galtek gene trap system is a valuable tool for discovering and functionally analyzing genes in stem cell differentiation.