I loko o nā makahiki he ʻumi i hala iho nei, ua ulu wikiwiki ka ʻenehana hoʻoponopono gene i hoʻokumu ʻia ma CRISPR, a ua hoʻohana maikaʻi ʻia i ka mālama ʻana i nā maʻi genetic a me ka maʻi kanesa i nā hoʻokolohua lapaʻau kanaka.I ka manawa like, ʻimi mau ka poʻe ʻepekema a puni ka honua i nā mea hana hou me ka hiki ke hoʻoponopono gene e hoʻoponopono i nā pilikia o nā mea hoʻoponopono gene a me nā mea hoʻoholo.

I Kepakemapa 2021, ua paʻi ka hui o Zhang Feng i kahi pepa i loko o ka puke puke ʻepekema [1], a ua ʻike ʻo ia i kahi ākea o nā transposters coded RNA guided nucleic acid enzymes a kapa ʻia ʻo ia ʻo Omega system (me ISCB, ISRB, TNP8).Ua ʻike pū ka haʻawina e hoʻohana ana ka ʻōnaehana Omega i kahi ʻāpana o RNA e alakaʻi i ka ʻoki ʻana i ke kaulahao pālua DNA, ʻo ia hoʻi ʻo ωRNA.ʻO ka mea nui, he liʻiliʻi loa kēia mau nucleic acid enzymes, ma kahi o 30% wale nō o CAS9, ʻo ia ka mea e hāʻawi ʻia paha lākou i nā cell.

Ma ʻOkakopa 12, 2022, ua paʻi ka hui o Zhang Feng i ka puke moʻolelo Nature i kapa ʻia: Structure of the Omega Nickase ISRB in Complex with ωrna a me Target DNA [2].

Hoʻopili hou ka haʻawina i ka ʻōnaehana microscope electron hauʻoli o ISRB-ωRNA a me ka paʻakikī DNA pahuhopu i ka ʻōnaehana Omega.

ʻO ISCB ke kupuna o CAS9, a ʻo ISRB ka mea like o ka nele o ka domain HNH nucleic acid o ISCB, no laila ʻoi aku ka liʻiliʻi o ka nui, ma kahi o 350 amino acids wale nō.Hāʻawi pū ka DNA i ke kumu no ka hoʻomohala hou a me ka hoʻololi ʻenehana.

ʻO IsrB alakaʻi ʻia e RNA he lālā o ka ʻohana OMEGA i hoʻopaʻa ʻia e ka IS200/IS605 superfamily o transposons.Mai ka loiloi phylogenetic a kaʻana like i nā kikowaena kūʻokoʻa, ʻo IsrB paha ka mea mua o IscB, ʻo ia ke kupuna o Cas9.

I Mei 2022, ua paʻi ʻo Cornell University's Lovely Dragon Laboratory i kahi pepa i loko o ka puke pai ʻepekema [3], e nānā ana i ke ʻano o IscB-ωRNA a me kāna hana o ka ʻoki ʻana i ka DNA.

Ke hoʻohālikelike ʻia me IscB a me Cas9, nele ʻo IsrB i ka HNH nuclease domain, ka REC lobe, a me ka hapa nui o ka PAM sequence-interacting domains, no laila ʻoi aku ka liʻiliʻi o IsrB ma mua o Cas9 (ma kahi o 350 amino acids wale nō).Eia naʻe, kaulike ka liʻiliʻi o IsrB e kahi RNA alakaʻi nui (ʻo kona omega RNA ma kahi o 300 nt ka lōʻihi).

Ua kālailai ka hui o Zhang Feng i ka cryo-electron microscope structure o IsrB (DtIsrB) mai ka pumehana anaerobic bacterium Desulfovirgula thermocuniculi a me kona paʻakikī o ωRNA a me DNA target.Ua hōʻike ʻia ka nānā ʻana i ka ʻōnaehana holoʻokoʻa o ka protein IsrB i kahi ʻano iwi kuamoʻo me ka protein Cas9.

Akā ʻo ka ʻokoʻa ka hoʻohana ʻana o Cas9 i ka REC lobe e hoʻomaʻamaʻa i ka ʻike maka, ʻoiai ʻo IsrB e hilinaʻi ana i kāna ωRNA, kahi ʻāpana i hana i kahi ʻano ʻekolu-dimensional paʻakikī e like me REC.

No ka hoʻomaopopo maikaʻi ʻana i ka hoʻololi ʻana o ka IsrB a me Cas9 i ka wā o ka hoʻomohala ʻana mai RuvC, ua hoʻohālikelike ka hui o Zhang Feng i nā ʻōnaehana paʻa DNA o RuvC (TtRuvC), IsrB, CjCas9 a me SpCas9 mai Thermus thermophilus.

Hoʻomaopopo ka hoʻomohala ʻana o IsrB a me kāna ωRNA pehea e ʻike ai ʻo IsrB-ωRNA a hoʻokaʻawale i ka DNA target, a hāʻawi pū i kumu no ka hoʻomohala hou ʻana a me ka ʻenekinia o kēia nuclease miniaturized.ʻO ka hoʻohālikelike ʻana me nā ʻōnaehana alakaʻi RNA ʻē aʻe e hōʻike ana i nā pilina hana ma waena o nā protein a me nā RNA, e hoʻonui ana i ko mākou ʻike i ka biology a me ka ulu ʻana o kēia mau ʻōnaehana like ʻole.

Nā loulou:

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