C‑Brick: A New Standard for Assembly of Biological Parts Using Cpf1

So far, several DNA assembly standards have been developed, enabling scientists to conveniently share and modify characterized DNA parts. However, a majority of the restriction endonucleases used in these standards bear short recognition sites (<i>e.g.</i>, 6 bps in BioBrick standard), which are widely distributed and need to be removed before further construction, causing much inconvenience. Although homing endonucleases, which recognize long DNA sequences, can be used for DNA assembly (<i>e.g.</i>, iBrick standard), long scars will be left between parts, limiting their application. Here, we introduce a new DNA assembly standard, namely C-Brick, which employs the newly identified class 2 type V CRISPR-Cas systems protein Cpf1 endonuclease. C-Brick integrates both advantages of long recognition sites and short scars. With C-Brick standard, three chromoprotein cassettes were assembled and further expressed in <i>Escherichia coli</i>, producing colorful pigments. Moreover, C-Brick standard is also partially compatible with the BglBrick and BioBrick standards

CADS: CRISPR/Cas12a-Assisted DNA Steganography for Securing the Storage and Transfer of DNA-Encoded Information

Because DNA has the merit of high capacity and complexity, DNA steganography, which conceals DNA-encoded messages, is very promising in information storage. The classical DNA steganography method hides DNA with a “secret message” in a mount of junk DNA, and the message can be extracted by polymerase chain reaction (PCR) using specific primers (key), followed by DNA sequencing and sequence decoding. As leakage of the primer information may result in message insecurity, new methods are needed to better secure the DNA information. Here, we develop a pre-key by either mixing specific primers (real key) with nonspecific primers (fake key) or linking a real key with 3′-end redundant sequences. Then, the single-stranded DNA (ssDNA) <i>trans</i> cleavage activity of CRISPR/Cas12a is employed to cut a fake key or remove the 3′-end redundant sequences, generating a real key for further information extraction. Therefore, with the Cas12a-assisted DNA steganography method, both storage and transfer of DNA-encoding data can be better protected