CMN Weekly (25 November 2022) - Your Weekly CRISPR Medicine News
Some of the best links we picked up around the internet
By: Gorm Palmgren - Nov. 25, 2022
Jennifer Doudna and co-workers have discovered that 0.4% of all phages encode CRISPR systems belonging to all six known CRISPR-Cas types. These include the new Casλ that recognizes double-stranded DNA using a uniquely structured CRISPR RNA (crRNA) and can induce genome editing in mammalian, Arabidopsis, and hexaploid wheat cells. The researchers believe that the viruses use CRISPR to compete with each other and manipulate gene activity in their hosts.
American researchers have developed a method for drag-and-drop genome insertion of large sequences without double-strand DNA cleavage using CRISPR-directed integrases. The technique (PASTE, programmable addition via site-specific targeting elements) uses a CRISPR-Cas9 nickase fused to reverse transcriptase and serine integrase for targeted genomic recruitment and integration of desired payloads. The authors demonstrate the integration of sequences as large as ~36 kilobases at multiple genomic loci across three human cell lines, primary T cells and non-dividing primary human hepatocytes.
Researchers in China have developed a CRISPR-Cas14-based platform for the facile, sensitive and versatile aptasensing of diverse targets. The fluorometric biosensor is named HARRY (highly sensitive aptamer-regulated Cas14 R-loop for bioanalysis) and works opposite most other detection systems: In the presence of the target, ssDNA-target assembly is formed via aptamer interaction, resulting in the inhibition of Cas14a activation, while in the absence of the target, the ssDNA activates Cas14a so trans-cleavage of the fluorescent reporter causes fluorescence enhancement.
The genome of β-thalassemia patients can be modified using the CRISPR/Cas9 technique to treat their disease. A review by Iranian researchers highlights the three main approaches that have been taken: 1) increase the expression of γ-globin and production of haemoglobin F, 2) reduction of the α-globin chain to prevent hemolysis of red blood cells by the accumulation of excessive α-globins, and 3) correction of the mutations causing β-thalassemia.