Related Experiment Video
Updated: Dec 11, 2025
Native Cell Membrane Nanoparticles System for Membrane Protein-Protein Interaction Analysis
Published on: July 16, 2020
Functional redundancy of structural proteins of the peritrophic membrane in Trichoplusia ni
1Department of Entomology, Cornell University, Geneva, NY, 14456, USA; School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China.
Abstract:
The peritrophic membrane (or peritrophic matrix) (PM) in insects is formed by binding of PM proteins with multiple chitin binding domains (CBDs) to chitin fibrils. Multi-CBD chitin binding proteins (CBPs) and the insect intestinal mucin (IIM) are major PM structural proteins. To understand the biochemical and physiological role of IIM in structural formation and physiological function of the PM, Trichoplusia ni mutant strains lacking IIM were generated by CRISPR/Cas9 mutagenesis. The mutant T. ni larvae were confirmed to lack IIM, but PM formation was observed as in wild type larvae and lacking IIM in the PM did not result in changes of protease activities in the larval midgut. Larval growth and development of the mutant strains were similar to the wild type strain on artificial diet and cabbage leaves, but had a decreased survival in the 5th instar. The larvae of the mutant strains with the PM formed without IIM did not have a change of susceptibility to the infection of the baculovirus AcMNPV and the Bacillus thuringiensis (Bt) formulation Dipel, to the toxicity of the Bt toxins Cry1Ac and Cry2Ab and the chemical insecticide sodium aluminofluoride. Treatment of the mutant T. ni larvae with Calcofluor reduced the larval susceptibility to the toxicity of Bt Cry1Ac, as similarly observed in the wild type larvae. Overall, in the mutant T. ni larvae, the PM was formed without IIM and the lacking of IIM in the PM did not drastically impact the performance of larvae on diet or cabbage leaves under the laboratory conditions.
Insights
Insect intestinal mucin (IIM) is not essential for peritrophic membrane (PM) formation or larval growth. However, its absence in the PM slightly reduced larval survival in the 5th instar.
Area of Science:
- Insect biology
- Biochemistry
- Molecular genetics
Background:
- The peritrophic membrane (PM) is a vital structure in the insect midgut, crucial for protection and digestion.
- Insect intestinal mucin (IIM) and multi-chitin binding domain proteins (CBPs) are key structural components of the PM.
- Understanding the specific roles of IIM in PM formation and function is essential for insect physiology research.
Purpose of the Study:
- To investigate the biochemical and physiological significance of IIM in the structural formation and function of the insect peritrophic membrane (PM).
- To generate and analyze Trichoplusia ni mutant strains lacking IIM using CRISPR/Cas9 technology.
Main Methods:
- CRISPR/Cas9 mutagenesis was employed to create Trichoplusia ni mutant strains lacking insect intestinal mucin (IIM).
- Mutant larvae were analyzed for the presence of IIM in the PM, protease activity, growth, survival rates, and susceptibility to baculovirus, Bacillus thuringiensis (Bt), and chemical insecticides.
- Larval responses to Bt toxins (Cry1Ac, Cry2Ab) and Calcofluor treatment were assessed.
Main Results:
- Mutant T. ni larvae successfully formed a peritrophic membrane (PM) lacking insect intestinal mucin (IIM).
- The absence of IIM in the PM did not alter midgut protease activity, larval growth on artificial diet or cabbage, or susceptibility to AcMNPV, Bt Dipel, Bt toxins (Cry1Ac, Cry2Ab), or sodium aluminofluoride.
- A slight decrease in 5th instar larval survival was observed in IIM-deficient mutants, and Calcofluor treatment affected susceptibility to Cry1Ac in both mutant and wild-type larvae.
Conclusions:
- Insect intestinal mucin (IIM) is not indispensable for the structural integrity of the peritrophic membrane (PM) or basic larval performance under standard laboratory conditions.
- While IIM absence does not drastically impair insect development or resistance to common pathogens and insecticides, it may subtly influence survival rates during later larval instars.
More Related Videos
10:20Studying Membrane Protein Trafficking in Drosophila Photoreceptor Cells Using eGFP-Tagged Proteins
Published on: January 21, 2022
10:31Detection of In Situ Protein-protein Complexes at the Drosophila Larval Neuromuscular Junction Using Proximity Ligation Assay
Published on: January 20, 2015
Related Concept Videos
01:57Protein Complexes with Interchangeable Parts
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order...
01:29Insertion of Multi-pass Transmembrane Proteins in the RER
The multipass transmembrane proteins are the type IV integral membrane proteins with multiple topogenic sequences determining their spatial arrangement in the ER membrane. Nearly all multipass proteins lack a cleavable signal sequence and use...
01:09Multi-pass Transmembrane Proteins and β-barrels
α-Helix containing multi-pass transmembrane proteins
Multi-pass transmembrane proteins such as...
01:29Tight Junctions
01:28Protein Translocation Machinery on the ER Membrane
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the...
01:21Structure of Porins