Figure 1From: Decreased gene expression from T7 promoters may be due to impaired production of active T7 RNA polymeraseProtein production levels under various conditions. SDS PAGE shows protein levels of SecB (A) and proOmpA (B). Gels were stained with Coomassie Blue. A. 15% PAGE of cell lysates from BL21(λDE3) containing pJW25. Arrow indicates SecB migration. Lane 1, molecular weight marker; lanes 2 (uninduced) and 3 (induced) are samples from cells immediately after transformation; lanes 4 (uninduced) and 5 (induced) are the same strain after 3 subculturings; lanes 6 (uninduced) and 7 (induced) after 8 subculturings; lanes 8 (uninduced) and 9 (induced) are BL21(λDE3) retransformed with the plasmid rescued from the strain in lane 6. We note that lane 8 was unintentionally underloaded. B. 10% PAGE of cell lysates from BL21(λDE3) containing pJGGV. Arrow indicates proOmpA migration. Lane 1, molecular weight marker; lanes 2 (uninduced) and 3 (induced) are samples from cells immediately after transformation; lanes 4 (uninduced) and 5 (induced) are the same strain after 3 subculturings; lanes 6 (uninduced) and 7 (induced) are BL21(λDE3) retransformed with the plasmid rescued from the strain in lane 4.Back to article page