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5916272 
Journal Article 
Tac promoter vectors incorporating the bacteriophage T7 gene 10 translational enhancer sequence for improved expression of cloned genes in Escherichia coli 
Lehmeier, B; Amann, E 
1992 
Yes 
Journal of Biotechnology
ISSN: 0168-1656
EISSN: 1873-4863 
23 
2 
153-165 
English 
1368056 
WOS:A1992HP66300003 
Two new plasmid expression vectors, pTacT7 and pTacT7L, have been constructed, which incorporate between the tac promoter and a downstream NcoI-HindIII polylinker sequence a synthetic sequence derived from the region upstream from gene 10 of bacteriophage T7 (g10-L). This sequence was recently shown to act as a translational enhancer (Olins et al., 1988) and was termed "Epsilon" (Enhancer of Protein Synthesis Initiation) element (Olins and Rangwala, 1989). In this communication we describe in detail the construction of ptacT7 and ptacT7L. Furthermore, we present evidence that the "Epsilon" element is able to enhance 3 to 20-fold the expression levels of two poorly expressed test genes encoding the human placental proteins PP9 and PP15. On the other hand, the expression levels of two highly expressed test genes encoding the human placental proteins PP4 and FXIIIa could not be further enhanced by the presence of the "Epsilon" element. These experiments show that the T7 gene 10 leader sequence can be utilized to improve the expression yields of otherwise poorly expressed heterologous genes in Escherichia coli. 
ESCHERICHIA-COLI; PROTEIN PRODUCTION; IMPROVED EXPRESSION; T7-TRANSLATIONAL ENHANCER; TAC PROMOTER VECTORS; HUMAN PLACENTAL PROTEINS