Patent ID: 8722361

Claim:
A method for production of a heterologous soluble polypeptide by a ciliate, the method comprising: (a) transforming said ciliate with a nucleic acid encoding a fusion protein comprising from N-terminus to C-terminus: (i) a mucocyst-targeting polypeptide of a mucocyst-targeted protein which is cleaved by a protease endogenous to said mucocyst; and (ii) a heterologous polypeptide; wherein expression of said fusion protein results in trafficking of said fusion protein to mucocysts within said ciliate and cleavage of said mucocyst-targeting polypeptide to release said heterologous soluble polypeptide within said mucocysts; (b) stimulating regulated secretion from said mucocysts of said ciliate, whereby an extracellular matrix is formed; and (c) separating said heterologous soluble polypeptide from said extracellular matrix and said ciliates.