Genom Düzenlemede CRISPR/Cas9 Çağı ve Lösemideki Uygulamaları

Year 2018, Volume: 8 Issue: 3, 232 - 248, 01.12.2018

Nurcan Gümüş , Burçin Tezcanlı Kaymaz

Abstract

Prokaryotik
canlıların immün sistemden adapte edilmiş olan CRISPR/Cas9  (Düzenli aralıklarla bölünmüş kısa palindromik
tekrar kümeleri/CRISPR ilişkili nukleaz 9) sistemi genom mühendisliği araçlarının arasına en son eklenen
RNA/protein kompleksidir. CRISPR/Cas9 teknolojisi, endonukleaz Cas9 ve kılavuz
RNA (sgRNA) aracılığı ile genomun istenen bir bölgesinde çift zincir
kırıklarının oluşumunu katalizler. Bu kırıkların (HR: Homolog Rekombinasyon [Homologous Recombination ya da HDR: Homology-Directed Repair]) ve (NHEJ:
Non-Homolog Uç Birleşmesi [Non-Homologous
End-Joining]) DNA tamir mekanizmaları kullanılarak, genom düzenlemesi
gerçekleştirilmektedir. CRISPR/Cas9 teknolojisi; bakteri suşlarının
tanımlanması, gen ve miRNA fonksiyonlarının belirlenmesi, genoma DNA fragmenti eklenmesi/çıkartılması,
gen susturma, transkripsiyonel ve epigenetik hedefleme ya da hastalık
modellerinin oluşturulması gibi çok geniş bir platformda kullanılmaktadır.

Kan/Kemik
iliği hastalıklarında lökositoz ile karakterize olan malignite gösteren lösemiler,
kromozomal yeniden düzenlemeler ya da mutasyonlar sonucunda gelişmektedir.
Günümüzde löseminin moleküler biyolojisi ile patogenezinin anlaşılması,
gelecekte çok daha etkin ve kişiye özgül tedavi imkanları sağlayacağından;
genom mühendisliği bu noktada önem kazanmaktadır. Çok geniş kullanım alanına
sahip olan CRISPR/Cas9 genom tasarımı teknolojisi, hastalık modellerinin
oluşturulması, gen ekleme ve susturulması, epigenetik regülasyon gibi alanlarda
kullanılarak, lösemi tedavisinde yeni bir fonksiyonel hedef ve tedavi çağı
başlangıcı olarak karşımıza çıkmaktadır. Bu derlemede, CRISPR/Cas9
teknolojisinin; tarihçesi, lokus birleşenleri, alt tipleri, adaptif bağışıklık
yanıtının oluşum aşamaları, Cas9 özgüllüğü ile bu teknolojinin çeşitli lösemi
tiplerinde kullanımıyla elde edilen tedavi kazanımlar ele alınacaktır. Ayrıca
bu derlemede CRISPR/Cas9 teknolojisinin, etik açısından değerlendirmelerine de
yer verilecektir.

Keywords

CRISPR/Cas9, genom düzenleme teknolojisi, lösemi, etik

CRISPR/Cas9 Age in Genome Editing and Leukemia Applications

Abstract

The
CRISPR/Cas9 ( clustered regularly interspaced short palindromic repeat/CRISPR-associated
nuclease-9) system which adapted from the prokaryotic immune system, is the
latest RNA/protein complex to be included among genomic engineering tools. CRISPR/Cas9
technology catalyzes the formation of double-strand breaks in DNA, according to
the Watson-Crick base pairing in a interested region of the genome, via
endonuclease Cas9 and guide RNA (sgRNA). Genomic regulation is performed by
repairing these fractures using (Homologous
Recombination or HDR:
Homology-Directed Repair)  and (NHEJ:
Non-Homologous End-Joining) DNA
repair mechanisms. CRISPR/Cas9 technology is used on a wide range of platforms,
 starting from identification of
bacterial strains, identification of gene and miRNA functions, genomic DNA
fragment insertion/deletion, gene silencing, transcriptional and epigenetic
targeting to creation of disease models. Leukemia, a malignancy characterized
by leukocytosis in the blood/bone marrow, is caused by chromosomal rearrangements
or mutations. Nowadays, genomic engineering is gaining an accelerating importance
in order to elucidate the pathogenesis and molecular biology of leukemia; thus
to provide more effective and personalised treatment opportunities in the
future. The widely used CRISPR/Cas9 genome design technologyrepresent a new
functional object for treatment of leukemia an the begining of a therapeutic
new era by being applied in areas such as creation of disease models, gene
insertion and silencing, epigenetic regulation. In this review, CRISPR/Cas9
technology; locus components, subtypes, stages of development of the adaptive
immune response, Cas9 specificity and therapeutic gains obtained via using this
technology in various types of leukemia will be discused. Also In this review,
the evaluation of CRISPR/Cas9 technology in terms of ethics will be included.

Keywords

CRISPR/Cas9, genome editing technology, leukemia, ethics

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