N'ime afọ iri gara aga, teknụzụ na-edezi mkpụrụ ndụ ihe nketa dabere na CRISPR etolitela ngwa ngwa, ma etinyere ya nke ọma na ọgwụgwọ ọrịa mkpụrụ ndụ ihe nketa na ọrịa kansa na nnwale ụlọ ọgwụ mmadụ.N'otu oge ahụ, ndị ọkà mmụta sayensị gburugburu ụwa na-ejikarị ngwá ọrụ ọhụrụ eme ihe nwere ikike idezi mkpụrụ ndụ ihe nketa iji dozie nsogbu nke ngwá ọrụ na-edezi mkpụrụ ndụ ihe nketa na mkpebi ndị dị adị.

Na Septemba 2021, ndị otu Zhang Feng bipụtara akwụkwọ n'ime akwụkwọ akụkọ Sayensị [1], wee chọpụta na ọtụtụ transposters koodu RNA na-eduzi enzymes nucleic acid wee kpọọ ya sistemụ Omega (gụnyere ISCB, ISRB, TNP8).Ọmụmụ ihe ahụ chọpụtakwara na usoro Omega na-eji akụkụ nke RNA na-eduzi ịcha DNA dual chain, ya bụ ωRNA.Nke ka mkpa, enzymes nucleic acid ndị a dị obere, naanị ihe dịka 30% nke CAS9, nke pụtara na enwere ike ibuga ha na sel.

Na Ọktọba 12, 2022, ndị otu Zhang Feng bipụtara na akwụkwọ akụkọ Nature akpọrọ: Structure of the Omega Nickase ISRB na Mgbagwoju anya na ωrna na Target DNA [2].

Ọmụmụ ihe gara n'ihu nyochara usoro microscope eletrọn oyi kpọnwụrụ nke ISRB-ωRNA yana mgbagwoju anya DNA na sistemụ Omega.

ISCB bụ nna ochie nke CAS9, ISRB bụkwa otu ihe ahụ nke enweghị ngalaba HNH nucleic acid nke ISCB, ya mere nha dị ntakịrị, naanị ihe dịka 350 amino acids.DNA na-enyekwa ntọala maka mmepe ọzọ na mgbanwe injinia.

IsrB na-eduzi RNA bụ onye otu ezinụlọ OMEGA nke nnukwu ezinụlọ IS200/IS605 nke transposons debere ya.Site na nyocha phylogenetic na ngalaba ngalaba pụrụ iche, IsrB nwere ike bụrụ ihe mmalite nke IscB, nke bụ nna ochie Cas9.

Na Mee 2022, Laboratory Lovely Dragọn nke Mahadum Cornell bipụtara akwụkwọ n'akwụkwọ akụkọ Science [3], na-enyocha nhazi nke IscB-ωRNA na usoro ya nke ịkpụ DNA.

E jiri ya tụnyere IscB na Cas9, IsrB enweghị HNH nuclease ngalaba, REC lobe, na ọtụtụ n'ime ngalaba PAM na-emekọrịta ihe, ya mere IsrB dị ntakịrị karịa Cas9 (naanị ihe dịka 350 amino acids).Agbanyeghị, obere nha nke IsrB na-edozi ya site na ntuziaka RNA buru ibu (omega RNA ya dị ihe dị ka 300 nt ogologo).

Ndị otu Zhang Feng nyochara usoro microscope cryo-electron nke IsrB (DtIsrB) site na nje bacteria anaerobic Desulfovirgula thermocuniculi na-ekpo ọkụ na mgbagwoju ya nke ωRNA na DNA lekwasịrị anya.Nyocha ihe owuwu gosiri na n'ozuzu nhazi nke protein IsrB na-ekekọrịta protein Cas9 ọkpụkpụ azụ.

Ma ihe dị iche bụ na Cas9 na-eji REC lobe iji kwado njirimara ebumnuche, ebe IsrB na-adabere na ωRNA ya, akụkụ nke na-emepụta usoro mgbagwoju anya atọ na-eme ka REC.

Iji ghọta nke ọma mgbanwe nhazi nke IsrB na Cas9 n'oge evolushọn sitere na RuvC, ndị otu Zhang Feng tụlere ebumnuche DNA-njikọ nke RuvC (TtRuvC), IsrB, CjCas9 na SpCas9 sitere na Thermus thermophilus.

Nyocha nhazi nke IsrB na ωRNA ya na-akọwa otú IsrB-ωRNA si ejikọta ọnụ ma na-agbaji DNA lekwasịrị anya, ma na-enyekwa ntọala maka mmepe na injinia nke obere obere ihe a.Ntụle ya na sistemu RNA ndị ọzọ na-egosipụta mmekọrịta arụ ọrụ n'etiti protein na RNA, na-akwalite nghọta anyị gbasara bayoloji na mgbanwe nke sistemu ndị a dị iche iche.

Njikọ:

1.https://www.science.org/doi/10.1126/science.abj6856

2.https://www.science.org/doi/10.1126/science.abq7220

3.https://www.nature.com/articles/s41586-022-05324-6