Thanks to all that replied. You might find this useful.
The question was: How to select an insect expression system for mammalian/viral glycoproteins? The following is a summary of the replies. *1. Baculovirus system* 1) For most proteins, the level of expression is far greater with bacuovirus. (Dima Klenchin) 2) An interesting system: BacMam. BacMam recombinant baculovirus in transporter expression: a study of BCRP and OATP1B1. Protein Expr Purif. 2006 Jun;47(2):591-8. Epub 2006 Jan 30. (Pius Stephen Padayatti) *2. Drosophila system* 1) With S2 you can get away without figuring out if the virus works, then again you probably need a stable cell line... (so which ever works...?) (OBS! cant do SeMet labelling with S2!! or if someone can please tell me) (Tommi Kajander) 2) We use S2 (drosophila cells) for generating our protein. Baculovirus is much more complicated to get running whereas S2 may generate slightly lower amounts of protein, but you will be able to get a system up and running quite quickly. In my experience I've had cases where I was only able to get very low virus titres for use, whereas the drosophila cells were able to go rapidly to expression for the same protein. The S2 cells are also a non-lytic system, so your protein will not get degraded so easily as they might in a lytic virus system. In my case I've tried them side-by-side and found S2 cells to be best (but that's obviously just in one case). (Paul A. McEwan) *3. Just use mammalian system!* 1) Why would you worry about insect expression systems if you already can secrete your constructs in mammalian cells? For such proteins, transient expression in HEK cells for example gives higher yields than baculo, is faster, cheaper, you can nicely control glycosylation, easily do Se-Met labelling and so on. Here are some references (PMID): 17355862, 17001101, 16823037, 11788735, 16082028. (Radu Aricescu) 2) I couldn't agree more with Radu. We had great success in expressing mg amounts of a secreted protein in HEK293 cells (with Radu's help :-) . The same protein was initially expressed in Sf9 cells but with much lower yields. Furthermore, we could very easily generate a stable HEK293 cell line expressing the same protein (at similar levels with transient transfections) with the Flp-In system in just a couple of weeks. We also have a LIC vector which is compatible with the Flp-In system. (Vangelis Christodoulou)
