Protospacer adjacent motif

A protospacer n'akụkụ motif (PAM) bụ 2-6-base ụzọ DNA usoro ozugbo na-eso usoro DNA nke Cas9 nuclease lekwasịrị anya na CRISPR usoro mgbochi nje.PAM bụ akụkụ nke nje virus ma ọ bụ plasmid na-awakpo, mana a naghị ahụ ya na mkpụrụ ndụ ihe nketa nke nje bacteria ma ya mere ọ bụghị akụkụ nke locus CRISPR nke nje bacteria. Cas9 agaghị ejikọta  ọ bụ kewaa usoro DNA a chọrọ ma ọ bụrụ na usoro PAM anaghị eso ya. PAM  ihe dị mkpa nke na-eme ka ọdịiche dị n'etiti onwe nje bacteria na DNA na-abụghị onwe ya, si otú a na-egbochi CRISPR locus ka nuclease jikọtara ya na-elekwasị anya ma na-ebibi ya. [1]

## Ndị na-agba ọsọ / ndị na-agba chaa chaa
N'ime mkpụrụ ndụ nje bacteria, CRISPR loci nwere "spacers" (DNA viral nke etinyere n'ime ebe CRISPR) na n'ụdị II usoro ihe mgbochi na-eme mgbanwe ka e kere site na viral ma ọ bụ plasmid DNA (nke a na-akpọ "protospacers").  Mgbe mbuso agha na-esote, ihe jikọrọ CRISPR dị ka Cas9 na-ejikọta na tracrRNA-crRNA mgbagwoju, nke na-eduzi Cas9 na usoro protospacer na-awakpo.  Mana Cas9 agaghị ekewa usoro protospacer ọ gwụla ma enwere usoro PAM dị n'akụkụ.  Onye na-ahụ maka nje bacteria CRISPR loci agaghị enwe usoro PAM, ya mere, a gaghị ebipụ ya site na nuclease, ma protospacer na nje virus ma ọ bụ plasmid ga-enwe usoro PAM, ya mere, Cas9 nuclease ga-agbaji.  4]  N'ime ngwa edezi genome, a na-ahazi oligonucleotide dị mkpirikpi nke a maara dị ka onye ndu RNA (gRNA) iji rụọ ọrụ nke mgbagwoju tracrRNA-crRNA n'ịghọta usoro mkpụrụ ndụ ihe nketa nwere usoro PAM na 3'-ngwụsị, si otú ahụ "na-eduzi" nuclease ka  usoro a kapịrị ọnụ nke nuclease nwere ike ịkpụ. 

## Usoro PAM
áká_ịkẹngạ|thumb|PAM na nha nke CRISPR DNA nucleases dị iche iche
Canonical PAM  usoro 5'-NGG-3', ebe "N" bụ nucleobase ọ bụla guanine ("G") nucleobases abụọ sochiri. RNA ndị nduzi nwere ike ibuga Cas9 na locus ọ bụla na genome maka nhazi mkpụrụ ndụ ihe nketa, mana enweghị nhazi nwere ike ime na saịtị ọ bụla ọzọ karịa otu Cas9 na-amata PAM.  na-ejikọta PAM canonical na Cas9 nuclease nke *Streptococcus pyogenes* (nke a họpụtara SpCas9), ebe PAM dị iche iche na-ejikarị protein Cas9 nke nje bacteria *Neisseria meningitidis*, Treponema denticola, na *Streptococcus thermophilus*. '-NGA-3' nwere ike ịbụ PAM na-adịghị arụ ọrụ nke ọma maka mkpụrụ ndụ mmadụ, mana arụmọrụ dịgasị iche na ọnọdụ genome.  meela mgbalị iji mepụta Cas9s iji mata PAM dị iche iche iji melite ikike nke CRISPR-Cas9 iji dezie mkpụrụ ndụ ihe nketa na ebe ọ bụla achọrọ.

Cas9 nke *Francisella novicida* na-amata usoro PAM 5'-NGG-3', mana emeela ya iji mata 5'-YG-3' (ebe "Y" bụ pyrimidine ), si otú a na-agbakwunye na ọnụọgụ nke Cas9 nwere ike.  Cpf1 nuclease nke *Francisella novicida* na-amata PAM 5'-TTTN-3' ma ọ bụ 5'-YTN-3'.

Ewezuga CRISPR-Cas9  CRISPR -Cpf1, enwere ọtụtụ nucleases na PAMs a na-achọpụtabeghị.

CRISPR/Cas13a (nke bụbu C2c2 ) sitere na nje bacteria *[[Leptotrichia shahii]]* bụ usoro CRISPR nke RNA na-eduzi nke na-elekwasị anya na usoro na RNA karịa DNA. PAM adịghị mkpa maka CRISPR -elekwasị anya na RNA, ọ bụ ezie na guanine na-emetụta ịdị irè nke ọma, a họpụtakwara ya dị ka "protospacer flanking site" (PFS). [1]

## GUIDE-Seq
 mepụtara teknụzụ a na-akpọ GUIDE-Seq iji nyochaa nkewa ndị na-abụghị nke a na-eme site na nhazi mkpụrụ ndụ ihe nketa dị otú ahụ. Enwere ike iji ihe achọrọ PAM mee ihe iji lekwasị anya  otu nucleotide heterozygous mutations mgbe ọ na-enweghị mmetụta ọ bụla na ụdị ala ọhịa.

## Hụkwa

* CRISPR
* CRISPR/Cpf1

## Njikọ mpụga

* Addgene CRISPR-Cas Nduzi

## Edensibia