Characterization of scFv-421, a single-chain antibody targeted to p53

Area of Science:

• Molecular Biology
• Immunology
• Cell Biology

Background:

• The tumor suppressor protein p53 plays a critical role in cellular regulation.
• Single-chain variable fragments (scFvs) are engineered antibodies with therapeutic potential.
• Targeting proteins to specific subcellular compartments influences their stability and function.

Purpose of the Study:

• To construct and express a single-chain antibody (scFv) that specifically binds the tumor suppressor protein p53.
• To investigate the intracellular expression and subcellular localization of engineered scFv antibodies in mammalian cells.
• To evaluate the impact of subcellular targeting and protein engineering on scFv expression levels.

Main Methods:

• Construction of a gene encoding an scFv antibody (scFv-421) from hybridoma cell RNA.
• Bacterial expression and purification of scFv-421 for binding validation.
• Intracellular expression of scFv antibodies (scFv-421, scFv-FRP5, scFv-R1R) in mammalian cells, targeted to nucleus, cytoplasm, or endoplasmic reticulum (ER).
• Addition of mouse immunoglobulin CK constant domain sequences to scFv constructs to enhance protein stability.

Main Results:

• Engineered scFv-421 specifically binds to the tumor suppressor protein p53.
• High expression levels of ER-targeted scFv proteins were observed in transfected COS-1 cells.
• Nuclear or cytoplasmic targeting resulted in lower scFv protein levels.
• Fusion with the CK constant domain moderately increased cytoplasmic expression of scFv-FRP5.

Conclusions:

• Engineered scFv antibodies can be successfully expressed and targeted to specific subcellular compartments in mammalian cells.
• Targeting scFv antibodies to the ER enhances their expression levels.
• Protein engineering strategies, such as adding constant domains, can modulate scFv expression and stability.