CRISPR Plasmid Maps: A Pre-cloning Review Checklist

A pre-cloning review checklist for CRISPR plasmid maps is a CRISPR-object gate, not a general frame walk and not a synthesis purchase packet. Do not ligate until the map shows a PAM that matches the nuclease, a spacer that does not include that PAM, a marker that holds in the intended host, and a promoter that is active there. What a Cas9 PAM is is the definition page. U6 versus T7 owns promoter class choice. Sequence-level design review owns frame, scars, and forbidden sites on any construct.

What a CRISPR Map Must Show Before Ligation

The search is pre-cloning review checklist for CRISPR plasmid maps. The objects are PAM, spacer, marker, and promoter. Addgene's CRISPR guide states that the PAM depends on the Cas protein and that the gRNA targeting sequence is the nucleotides that precede the PAM in genomic DNA. That sequence is cloned into a gRNA expression plasmid. It does not include the PAM or the scaffold. A gRNA design note repeats the same operational rule: do not include the PAM in a synthesized or expressed guide. The PAM must exist in the target.

Bacterial and mammalian markers are separate checks. A plasmid can carry amp for cloning and puro for mammalian selection. Confirm each against the host that will see that drug. Promoter species is the fourth object: a U6 cassette does not answer a T7 in-vitro job, and a bacterial promoter will not drive the guide in mammalian cells. This page records those four objects. It does not re-decide U6 versus T7.

Pre-Cloning Review Steps

1. Write the Cas protein and the PAM it requires on the review note. If the map is silent on the nuclease, reject.
2. Highlight the spacer on the map. Confirm the cloning oligos encode the spacer and not the PAM. Reject any oligo set that appends NGG or another PAM as if it were part of the insert.
3. Name the bacterial marker and, if the plasmid will enter mammalian cells, the mammalian marker. Confirm the host is not already resistant.
4. Name the promoter that drives the guide or the Cas cassette and the species in which it must work. If the species does not match, stop and open the U6-versus-T7 page instead of inventing a fix here.
5. Write freeze or reject with coordinates a second reader can find. Do not ligate on a verbal “the PAM is fine.”

After the gate, ZettaCRISPR can be the place the guide is designed, and ZettaGene can hold the plasmid map. Official product pages mention CRISPR guide-RNA design and restriction, Gibson, or homologous-alignment simulation. Golden Gate is not a listed Zetta cloning simulation. Do not write it into this review as a product feature.

Expected Result and Verification

The expected result is a map note that points to four coordinates or feature names: PAM-nuclease pair, spacer without PAM, marker pair, promoter species. Verification is a second reader hitting those four without asking the designer to interpret the cartoon. Verification fails if the spacer includes the PAM, if only one of two markers was checked, or if the promoter species is assumed from the lab's usual cassette. If oligos are already ordered, this gate is late. Reconstruct, then decide whether to relabel or to reorder.

Failures That Waste a Cloning Week

The expensive failure is a guide that cannot cut because the PAM was designed into the oligo and omitted from the genome, or the reverse. The next is a beautiful mammalian cassette cloned into a strain that already ignores the bacterial marker, so no colonies appear and the science is blamed. Frame shifts and leftover scars still matter, but they are the general sequence-level page. A synthesis PO that has not listed the confirmed sequence is the gene-synthesis checklist. Keep those jobs off this ol. This page only closes CRISPR map objects before anyone ligates.

Frequently Asked Questions

Should the PAM sequence be included in CRISPR cloning oligos?

No. The PAM must exist in the genomic target. It does not belong in the guide insert.

Is a CRISPR pre-cloning review the same as a sequence-level design review?

No. Sequence-level review owns frame, scars, and forbidden sites on any construct. This page owns PAM, marker, and promoter on a CRISPR map.