March 10, 2019

CRISPR quality improvement tested

March 10, 2019/ Robert P. Ruggiero, phd

CRISPR Base Editor Takes Diagnostic and Remedial Exams

CRISPR quality improvement tested. Genome Media.

Whether a CRISPR-based editing tool makes the grade or needs remedial work isn’t clear until it is subjected to testing, thorough and systematic testing. Consequently, scientists based at South Korea’s Institute for Basic Science (IBS) are administering the CRISPR equivalent of standardized tests. Rather than present CRISPR tools with a #2 pencil and a fill-in-the-oval sheet, the scientists provide different guide RNAs. Then the scientists use genome sequencing to check for errors such as off-target effects.

CRISPR off-target errors

March 09, 2019/ Robert P. Ruggiero, phd

A CRISPR spin-off causes unintended typos in DNA

Even the best editor sometimes introduces typos. That’s true whether the editor is human or a version of the much-heralded gene-editing tool CRISPR.

One type of CRISPR gene editor that changes individual DNA bases, rather than cutting DNA, introduces more unwanted mutations than expected in mouse embryos and rice plants, researchers report. Those mistakes occurred in places where the tool wasn’t supposed to make changes. Another tested base editor, however, didn’t make the undesirable edits. The results were described in two studies published online February 28 in Science.

GenomeWeb covers off-target effects in CRISPR Cytosine Base Editors

March 04, 2019/ Robert P. Ruggiero, phd

CRISPR Researchers Find Cytosine Base Editors Generate Substantial Off-Target Effects

GenomeWeb covers off-target effects in CRISPR Cytosine Base Editors

NEW YORK (GenomeWeb) – In a study published in Science late last week, researchers from the US, China, and Germany reported a new method they've developed to detect off-target mutations created from editing one blastomere of two-cell mouse embryos using either CRISPR-Cas9 or one of two base editing technologies.

This method — named GOTI (Genome-wide Off-target analysis by Two-cell embryo Injection) — found that off-target single nucleotide variants (SNVs) were rare in embryos edited by CRISPR-Cas9 or the adenine base editor 7.10 (ABE7.10), which both caused off-target effects with a frequency close to the spontaneous mutation rate. However, the researchers also found that the cytosine base editor 3 (BE3) induced SNVs with frequencies more than 20-fold higher than the spontaneous mutation rate.

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