Team:UST Beijing/Footsteps

RFP Parts Evaluation

Evaluation and characterization of a highly engineered RFP gene (BBa_J04450): thermo sensitive expression pattern and secondary structure of mRNA.

Red fluorescent protein, which is also called RFP, is widely used as indicator or reporter gene in iGEM and other researches because it is easy for observation and measurement. During our experiments, RFP was also used in our experiment design. Parts from igem delivered plates, BBa_J04450, pSB1AC3 (http://parts.igem.org/Part:BBa_J04450), is an expression vector with highly engineered RFP gene sequence. But in our experiment, we found some very interesting character of this part. After that, we repeated the same procedures to make eliminate possible operation errors which make us believe that the phenomenon we observed can be reproducible. Since temperature was the only factor that has influenced the expression rate of rfp, there are several possible mechanisms our team members have proposed to explain it. The first kind of opinion is that, under lower temperature, the cells’ metabolism rate is also lowered, which means slower rate of transcription and expression rate. When cells facing with such problems, they might choose to appropriate their limited energy and material to the expression of house-keeping genes. On the other hand, 28 centigrade temperature is probably not cold enough to cause too much survival pressures for bacteria but may induce some other change to the RFP gene transcription and expression. Long hairpin structure caused by long reverted repeat sequences might hinder the movement of ribosome along mRNA, which means the lower rate of expression.