Please note there is a typo in the text. Where it reads:
'All L1 backbones used within this protocol give standardised overhangs of GGAG and GCTT when digested with BsaI. As a result, the first L0 module in the sequence to be cloned in must contain a GGAG overhang at the 5’ end and the last module must contain a GCTT overhang at the 3’ end.'

The GCTT should be CGCT, and should therefore read:

'All L1 backbones used within this protocol give standardised overhangs of GGAG and CGCT when digested with BsaI. As a result, the first L0 module in the sequence to be cloned in must contain a GGAG overhang at the 5’ end and the last module must contain a CGCT overhang at the 3’ end.'
6/1/2018 5:43:04 AM Reply