Polyhedrin -Positive BmNPV Bac to Bac

Customers who are looking for a low cost large-scale recombinant protein expression service could consider our Polyhedrin-Positive BmNPV Bac to Bac system.

Improvements had been made on the original silkworm expression system to overcome its shortcomings. Polyhedrin coding sequence was replaced by a string of element to establish a Polyhedrin-Negative Bac to Bac System (Figure 1.), which can infect the hemocoel (only) and efficiently expression target protein on a small-scale after the dorsal recombinant BmBacmid injection. However, the laborious dorsal injection makes the Polh Negative BEVS not ideal for large scale protein production anymore.

Our Polh⁺ baculovirus is designed to support oral infection, solving the speed limitation step of BmNPV.

• Essential Component of Polyhedrin-Positive Bac to Bac System 

The Polyhedrin-Positive Bac to Bac System is similar to the Negative one. The only difference is that there is a fragment which contains a p10 promoter and a Polyhedrin sequence is insert to the BmBacmid. The manipulated BmBacmid is named as BmBacmid (polh⁺) and then is transferred into Escherichia coli DH10.

The Polyhedrin-Positive BmNPV Bac to Bac system generally consists of:

• A donor plasmid which carries the interest fragment (Figure 2. A) 
• A polyhedrin-positive BmBacmid— BmBacmid (polh⁺) (Figure 1.)
• The E. coli DH10BmBac (polh⁺) which hosts BmBacmid and contains a helper plasmid (Figure 2. B).

Figure 1. Structure of BmBacmid in Polyhedrin-Positive Bac to Bac System

Expression Process of Polyhedrin-Positive BmNPV Bac to Bac System

• Subclone the gene of interest into donor plasmid between the two Tn7 site, downstream of the polyhedrin promoter
• Transform the recombinant donor plasmid into E. coli DH10BmBac (polh⁺) for transposition
• Colony selection by x-gal culture medium
• Extract the recombinant bacmid from E. coli DH10BmBac (polh⁺) and transfect the silkworm BmN cells to generate recombinant baculovirus
• Collect the medium supernatant and orally infect the larvae
• Harvest the target protein

This system mainly relies on Tn7 site-specific transposition between donor plasmid and BmBacmid to generate recombinant baculovirus. Relies on the simultaneous expression of polyhedrin and foreign to embed infectious recombinant baculovirus.

Our Customized Service

Expression process (Figure 2):

Figure 2. Expression Process of Polyhedrin-Positive BmNPV Bac-to-Bac System

Why Choose Polyhedrin-Positive BmNPV Bac to Bac System

polh⁺ virus is highly infectious to the midgut epithelial cells and mediate infectious to larva transmission. Suitable for large-scale protein production.

Our Polyhedrin-Negative BmNPV Bac to Bac protein expression process is so sample that it only takes 3-4 weeks to obtain the target protein. Especially suitable for customers who requires small-scale and fast expression.

• Simple administration. Just feed the larvae with virus-smeared mulberry leaves and the infection symptoms can be observed 4-5 days later
• Highly infectious. The recombinant virus is as infectious as the wild ones, more than 90% silkworm show symptoms after administration
• Low cost. Silkworm larvae has large body and low rearing cost
• High efficiency. No need for the laborious dorsal injection. Hundreds of larvae can be infected at the same time
• High yield. The expression of foreign is driven by the strong polyhedrin promoter. Simultaneously, the expression of polyhedrin is driven by a relatively weaker p10 promoter  

Relevant service

Polh-negative BmBacmid

Polyhedrin locus was knocked out, highly infectious for hemocoel tissues and cultured cells, requires neither transfection nor amplification. Suitable for small-scale fast protein production.

Creative BioMart’s deeply developed research platform endows it with expertise in gene manipulation. We are always committed to improving the existing system to maximize its advantages. Browse our service instrument to decide a suitable BmNPV BEVS expression approach for your protein or contact us for help. If you had already made your own expression plan which is beyond our list, our edge-cutting technology platform still able to provide assistance for you. All you need to do is to contact us and put forward your requirements.