TABLE 1:

Primers.

Primer	Sequence (5’ to 3’)	Notes
Primer 1	AATGATACGGCGACCACCGAGATCTACACGAATGACACACAGGAACTACGCG	Contains the P5 Illumina adaptor
Primer 2	CAAGCAGAAGACGGCATACGAGATNNNNNNGATTTTCAAATGGCGACCTGC	Contains the P7 Illumina adaptor and a barcode, written here as “NNNNNN”. We have used the following barcode sequences: ATCACG, CGATGT, TTAGGC, TGACCA, ACAGTG, GCCAAT, CAGATC, ACTTGA, GATCAG, TAGCTT, GGCTAC, CTTGTA, AGTCAA, AGTTCC, ATGTCA, CCGTCC, GTCCGC, GTGAAA, GTGGCC, GTTTCG, CGTACG, GAGTGG, ACTGAT, ATTCCT
Primer 3	CGGTGCCACTTTTTCAAGTTGATAACGGACTAGCCTTATTTTAACTTGCTATTTCTAGCTCTAAAAC	Used to sequence sgRNAs using Illumina sequencing
Primer 4	GCGCGACAGAAAGCCCCTTCGAAGAGCGCACAGGGAGGAAGCAGGCCTCTGCAGGTCGCCATTTGAAAATC	Used to sequence barcodes using Illumina sequencing
Primer 5	TTCTGGTAAATGGGGATGTCAAGTT	Used to clone the CRISPR library into pU6-DHFR
Primer 6	AACTTGCTATTTCTAGCTCTAAAAC	Used to clone the CRISPR library into pU6-DHFR