Difference between revisions of "Part:BBa K4245001"

Latest revision as of 16:04, 10 October 2022

Spinach aptamer with LacI repression

This part produces the fluorescent RNA aptamer Spinach (BBa_K734002) under the control of IPTG. Originally generated by the Jaffrey Lab at Cornell University, the Spinach aptamer is a fluorescent light-up aptamers (FLAP) that binds to 3’5-difluoro-4-hydroxybenzylidene imidazolinone (DFHBI), a small dye derived from the GFP fluorophore, to produce fluorescence (Paige et al., 2011). As shown in Figure 1, the aptamer and DFHBI bind together to produce green fluorescence, which has roughly 50% of the fluorescence intensity of enhanced GFP (Neubacher & Hennig, 2018). However, FLAPs can be more effective than GFP in biosensing assince they bind to a fluorophore after transcription (RNA), while GFP requires additional translation for expression. Similar to other FLAPs, Spinach is expressed within a transfer RNA (tRNA) scaffold, which shields the RNA from misfolding and degradation (Paige et al., 2011).

The LacI protein represses the inducible promoter (BBa_R0010), which stops downstream transcription of the Spinach aptamer. When IPTG is present, LacI is inhibited, allowing for the transcription of the aptamer. Once DFHBI binds to the aptamer, the RNA-fluorophore complex produces a quantifiable green fluorescence.

Sequence and Features