Secretion of functional human enzymes by Tetrahymena thermophila.
BACKGROUND
The non-pathogenic ciliate Tetrahymena thermophila is one of the best-characterized unicellular eucaryotes used in various research fields. Previous work has shown that this unicellular organism provides many biological features to become a high-quality expression system, like multiplying to high cell densities with short generation times in bioreactors. In addition, the expression of surface antigens from the malaria parasite Plasmodium falciparum and the ciliate Ichthyophthirius multifiliis suggests that T. thermophila might play an important role in vaccine development. However, the expression of functional mammalian or human enzymes remains so far to be seen.


RESULTS
We have been able to express a human enzyme in T. thermophila using expression modules that encode a fusion protein consisting of the endogenous phospholipase A1 precursor and mature human DNaseI. The recombinant human enzyme is active, indicating that also disulfide bridges are correctly formed. Furthermore, a detailed N-glycan structure of the recombinant enzyme is presented, illustrating a very consistent glycosylation pattern.


CONCLUSIONS
The ciliate expression system has the potential to become an excellent expression system. However, additional optimisation steps including host strain improvement as wells as measures to increase the yield of expression are necessary to be able to provide an alternative to the common E. coli and yeast-based systems as well as to transformed mammalian cell lines.
Weide
Thomas
T
Cilian AG, Johann-Krane-Weg 42, D-48149 Münster, Germany. weide@cilian.de
Herrmann
Lutz
L
Bockau
Ulrike
U
Niebur
Nadine
N
Aldag
Ingo
I
Laroy
Wouter
W
Contreras
Roland
R
Tiedtke
Arno
A
Hartmann
Marcus W W
MW
D000818:Animals; D001483:Base Sequence; D003850:Deoxyribonuclease I / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D006031:Glycosylation; D006801:Humans; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism*; D016808:Tetrahymena thermophila / Q000235:genetics*; D014170:Transformation, Genetic
D011993:Recombinant Fusion Proteins; D003850:Deoxyribonuclease I