Difference between revisions of "Part:BBa K1758100"

Revision as of 23:46, 18 September 2015

Translation enhancing 5-UTR containing g10-L RBS

This sequence contains a 5' untranslated region (5'-UTR) and a strong ribosomal binding site from bacteriophage T7, named g10-L. This sequence greatly enhances translation of a following gene. The enhancing effect relies on the regulation of mRNA binding to and release of the ribosome S30 subunit (for details see [http://www.ncbi.nlm.nih.gov/pubmed/2676996 Olins et al. 1989] and [http://www.ncbi.nlm.nih.gov/pubmed/23927491 Takahashi et al. 2013]).

g10-L is a strong RBS in E. coli but also well suited for foreign gene expression ([http://www.nature.com/nbt/journal/v9/n5/abs/nbt0591-477.html Rangwala et al. 1991]).

Usage and Biology

This part includes a RBS and a translation enhancing sequence. It improves the expression of a following gene when cloned in front of it compared to other RBS, for example B0034. The sequence of this part is derived from Olins et al. 1989 and ribosome binding analysis from Takahashi et al. 2013.

Design considerations

• AATAATTTTGTTTTAACTTTAA
• To increase the efficiency of translation initiation, the T7 g10 leader sequence can be employed. This sequence contains the socalled epsilon motif TTAACTTTA (Spirin and Swartz, 2008), and was originally described by Olins et al. 1988. It enhances the binding of the mRNA to the 16 S rRNA (Olins et al. 1988; Olins, Rangwala 1989; Takahashi et al. 2013), and Olins et al. showed that this sequence can massively improve heterologous gene expression in E. coli (Olins et al. 1988).
• poly-A-spacer
• With kinetic studies, Takahashi et al. showed that a spacer between the epsilon motive and the RBS improves the translation rate in vitro. This works when the spacer does not interact with the 30S subunit of the ribosome, which is the case for example for an all-adenine spacer (Takahashi et al. 2013). They further determined a 10-A-spacer as suitable when using E. coli S30 extracts instead of the PURE system.
• GAAGGAG
• The effect of the ribosome binding site (RBS) on in vitro translation has been investigated extensively (Karig et al. 2012; Lentini et al. 2013; Takahashi et al. 2013). Most important for an efficient reaction is a defined distance (4-9 bases) of the RBS to the following start codon (Karig et al. 2012; Lentini et al. 2013). The strength of the RBS has a minor effect as long as it is not too weak (Karig et al. 2012; Takahashi et al. 2013).
• AATAATCT
• According to Lentini et al. 2013, the sequence composition between RBS and start codon affects the expression level of the following gene. An AT-rich region gives the best results, whereas expression is lower with the biobrick scar TACTAGAG for example (Lentini et al. 2013)

Sequence and Features