Question:

Is there a way to 'direct' a protein towards secretion versus insoluble inclusions for genes in general? A leader sequence perhaps? Has anything in particular worked well in BV systems?

Resolution:

A secretion signal peptide is what does the trick. The best one I've used it EGT. It's referenced in the literature; Ecdysteroid Glucosyl Transferase, IF I remember correctly. With that said, however, a SP is not the only thing necessary. The protein must have 'secretable characteristics'. Most proteins that are naturally secreted work well. Many even work quite well with their native SP, provided they're eukaryotic proteins. If proteins really form inclusion bodies, slowing the expression down to a rate consistent with the golgi processing apparatus is the main idea. Less active promoters and lower temperature are two viable approaches to this effort, especially if the promoters are expressed earlier such as the 'Basic Protein' promoter.