Fig. 2
![Fig. 2](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs13578-019-0350-7/MediaObjects/13578_2019_350_Fig2_HTML.png)
A schematic diagram of overlapping primers amplification. AF1, AF2, AF3 and Tracr-R are overlapping primer. The sgRNA transcription template consists of three parts: T7 promotor (Red marked), the designed sequence of sgRNA (blue background marked), the conserved sequence of sgRNA (the rest of the sequence)