A new Trichoplusia ni cell line for membrane protein expression using a baculovirus expression vector system

Area of Science:

• Insect cell line development
• Biotechnology
• Membrane protein expression

Background:

• Baculovirus expression vector systems (BEVS) are widely used for protein production.
• Evaluating new insect cell lines is crucial for optimizing recombinant protein yields.
• Membrane proteins present unique challenges for expression and production.

Purpose of the Study:

• To establish and characterize a new Trichoplusia ni (Tn) cell line, MSU-TnT4 (TnT4), for BEVS.
• To assess the potential of TnT4 cells for membrane protein production.
• To compare the expression levels of membrane proteins in TnT4 cells versus established cell lines.

Main Methods:

• Established the MSU-TnT4 cell line from Trichoplusia ni embryos.
• Constructed recombinant baculoviruses to express a human neurotensin receptor 1-GFP fusion protein.
• Evaluated membrane protein synthesis via GFP intensity and secreted alkaline phosphatase (SEAP) expression.
• Determined cell doubling time and compared protein expression levels with Sf21 cells.

Main Results:

• TnT4 cells exhibited a doubling time of 21 hours.
• TnT4 cells expressed the membrane-GFP fusion protein at approximately twice the level of Sf21 cells.
• Expression of secreted alkaline phosphatase (SEAP) was comparable between TnT4 and Sf21 cells.
• Recombinant baculovirus expression of membrane-GFP fusions proved effective for cell line evaluation.

Conclusions:

• The MSU-TnT4 cell line is a promising new candidate for BEVS, particularly for membrane protein production.
• TnT4 cells demonstrate superior expression levels for membrane-GFP fusion proteins compared to Sf21 cells.
• This study validates the use of membrane-GFP fusion proteins in recombinant baculoviruses as a rapid screening method for new cell lines in BEVS.