Transgenic mice: a tool for the study of tissue-specific gene expression

Area of Science:

• Molecular Biology
• Genetics
• Developmental Biology

Background:

• Transgenic mice are created by introducing cloned DNA into the mouse genome, typically via pronuclear microinjection.
• These models are valuable tools for dissecting the cis-acting DNA elements that govern tissue-specific gene expression.

Purpose of the Study:

• To investigate the sufficiency of known regulatory DNA sequences for achieving tissue-specific gene expression in vivo using transgenic mouse models.
• To compare the expression patterns of the mouse albumin gene and the human insulin gene in transgenic mice.

Main Methods:

• Generation of transgenic mice carrying either the mouse albumin gene or the human insulin gene.
• Analysis of gene expression patterns in different tissues of the obtained transgenic mouse lines.
• Introduction of the chicken immunoglobulin (Ig) lambda light chain gene into the mouse genome to study gene rearrangement.

Main Results:

• Regulatory sequences for the mouse albumin gene, sufficient in hepatoma cells, failed to induce expression in transgenic mice.
• A short upstream sequence for the human insulin gene, sufficient in insulinoma cells, successfully directed expression in transgenic mice.
• Rearrangement of the introduced chicken Ig lambda light chain gene was observed in transgenic mouse lines, indicating successful V(D)J recombination.

Conclusions:

• In vivo gene expression regulation in transgenic mice can differ significantly from cell culture observations.
• The study highlights the complexity of cis-acting elements and the potential influence of the in vivo environment on gene regulation.
• Transgenic mouse models provide a powerful system for studying gene regulation and developmental processes like immunoglobulin gene rearrangement.