Bacteriophage T7 RNA polymerase-based expression in Pichia pastoris.
A novel Pichia pastoris expression vector (pEZT7) for the production of recombinant proteins employing prokaryotic bacteriophage T7 RNA polymerase (T7 RNAP) (EC 2.7.7.6) and the corresponding promoter pT7 was constructed. The gene for T7 RNAP was stably introduced into the P. pastoris chromosome 2 under control of the (endogenous) constitutive P. pastoris glyceraldehyde-3-phosphate dehydrogenase (GAP) promoter (pGAP). The gene product T7 RNAP was engineered to contain a nuclear localization signal, which directed recombinant T7 RNAP to the P. pastoris nucleus. To promote translation of uncapped T7 RNAP derived transcripts, the internal ribosomal entry site from hepatitis C virus (HCV-IRES) was inserted directly upstream of the multiple cloning site of pEZT7. A P. pastoris autonomous replicating sequence (PARS1) was integrated into pEZT7 enabling propagation and recovery of plasmids from P. pastoris. Rapid amplification of 5' complementary DNA ends (5' RACE) experiments employing the test plasmid pEZT7-EGFP revealed that transcripts indeed initiated at pT7. HCV-IRES mediated translation of the latter mRNAs, however, was not observed. Surprisingly, HCV-IRES and the reverse complement of PARS1 (PARS1rc) were both found to display significant promoter activity as shown by 5' RACE.
Institut für Technische Mikrobiologie, Hochschule Mannheim, 68163 Mannheim, Germany.
Birgit
B
Hobl
Björn
B
Hock
Sandra
S
Schneck
Reinhard
R
Fischer
Matthias
M
Mack
D017123:Bacteriophage T7 / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D005786:Gene Expression Regulation; D005822:Genetic Vectors / Q000235:genetics; D016174:Hepacivirus / Q000235:genetics; D010843:Pichia / Q000235:genetics*; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics*
D011994:Recombinant Proteins; D014764:Viral Proteins; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases
Internal ribosomal entry site; Pichia pastoris; Pichia pastoris autonomous replicating sequence; Recombinant protein production; T7 RNA polymerase