Fig. 1
Schematic representation of the CRISPR/Cas9 genome editing systems in H. insolens. ① Cas9 expression cassette. Ptef1: tef1 promoter from M. thermophila. ② sgRNA expression cassette. P5S rRNA (light gray): the A. niger 5S rRNA gene with its 338-bp upstream promoter. HDV (light green): the hepatitis delta virus ribozyme; tRNAGly (purple): the transfer RNA for glycine from H. insolens. The dotted box frames up the structure of tRNAGly–sgRNA; the red arrows indicate excision sites by RNase P and RNase Z. ③ Donor DNA. armL (bright brown): the upstream homologous arm; armR (bright brown): downstream homologous arm; NGG (blue): the PAM sequence; DSB: double-strand break; Hyg (light brown): hygromycin B resistance gene expression cassette