RNA has characteristics that are important in human gene expression (i.e. alternative splicing of mRNA, noncoding RNA). Therefore, a modular RNA binding protein is an invaluable tool for gene regulation. The PUF domain of human PUM1 gene contains eight tandem repeats, each recognizing one of the four nucleotide bases. In theory, a PUF protein can be programmed to recognize any 8-nt ssRNA sequence. Here we demonstrate that PUF can be tethered with other functional domains for applications in E. Coli. Specifically, we show that a PUF/endonuclease fusion protein acts as RNA scissors, silencing gene expression through site specific mRNA cleavage. PUF was also tethered to split GFP to test its ability to co-localize proteins using a RNA scaffold. PUF biobricks offer a wide range of possible functions including gene expression modulation and scaffolding of metabolic pathways.
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