In early 2022, four European bison are to be released in a controlled area of a nature reserve outside Canterbury – a move conservationists hope will regenerate ecosystems

In early 2022, four European bison are to be released in a controlled area of a nature reserve outside Canterbury – a move conservationists hope will regenerate ecosystems

by Wenting Bu, Zarina Levitskaya, Zhi Yang Loh, Shengyang Jin, Shibom Basu, Rya Ero, Xinfu Yan, Meitian Wang, So Fong Cam Ngan, Siu Kwan Sze, Suet-Mien Tan, Yong-Gui Gao

Kindlin-1, -2, and -3 directly bind integrin β cytoplasmic tails to regulate integrin activation and signaling. Despite their functional significance and links to several diseases, structural information on full-length kindlin proteins remains unknown. Here, we report the crystal structure of human full-length kindlin-3, which reveals a novel homotrimer state. Unlike kindlin-3 monomer, which is the major population in insect and mammalian cell expression systems, kindlin-3 trimer does not bind integrin β cytoplasmic tail as the integrin-binding pocket in the F3 subdomain of 1 protomer is occluded by the pleckstrin homology (PH) domain of another protomer, suggesting that kindlin-3 is auto-inhibited upon trimer formation. This is also supported by functional assays in which kindlin-3 knockout K562 erythroleukemia cells reconstituted with the mutant kindlin-3 containing trimer-disrupting mutations exhibited an increase in integrin-mediated adhesion and spreading on fibronectin compared with those reconstituted with wild-type kindlin-3. Taken together, our findings reveal a novel mechanism of kindlin auto-inhibition that involves its homotrimer formation.

by Haihua Xie, Xianglian Ge, Fayu Yang, Bang Wang, Shuang Li, Jinzhi Duan, Xiujuan Lv, Congsheng Cheng, Zongming Song, Changbao Liu, Junzhao Zhao, Yu Zhang, Jinyu Wu, Caixia Gao, Jinwei Zhang, Feng Gu

CRISPR-Staphylococcus aureus Cas9 (CRISPR-SaCas9) has been harnessed as an effective in vivo genome-editing tool to manipulate genomes. However, off-target effects remain a major bottleneck that precludes safe and reliable applications in genome editing. Here, we characterize the off-target effects of wild-type (WT) SaCas9 at single-nucleotide (single-nt) resolution and describe a directional screening system to identify novel SaCas9 variants with desired properties in human cells. Using this system, we identified enhanced-fidelity SaCas9 (efSaCas9) (variant Mut268 harboring the single mutation of N260D), which could effectively distinguish and reject single base-pair mismatches. We demonstrate dramatically reduced off-target effects (approximately 2- to 93-fold improvements) of Mut268 compared to WT using targeted deep-sequencing analyses. To understand the structural origin of the fidelity enhancement, we find that N260, located in the REC3 domain, orchestrates an extensive network of contacts between REC3 and the guide RNA-DNA heteroduplex. efSaCas9 can be broadly used in genome-editing applications that require high fidelity. Furthermore, this study provides a general strategy to rapidly evolve other desired CRISPR-Cas9 traits besides enhanced fidelity, to expand the utility of the CRISPR toolkit.

The latest coronavirus news updated every day including coronavirus cases, the latest news, features and interviews from New Scientist and essential information about the covid-19 pandemic

The latest coronavirus news updated every day including coronavirus cases, the latest news, features and interviews from New Scientist and essential information about the covid-19 pandemic

A grid of speakers fixed to a window can cut the noisiness of urban traffic in half, reducing the sound coming through an open window by up to 10 decibels

A grid of speakers fixed to a window can cut the noisiness of urban traffic in half, reducing the sound coming through an open window by up to 10 decibels

A fossil of an ancient giant tusked dolphin lacks the extra vertebrae and short pectoral bones that make fast swimmers of dolphins and baleen whales, which later independently evolved these traits

A fossil of an ancient giant tusked dolphin lacks the extra vertebrae and short pectoral bones that make fast swimmers of dolphins and baleen whales, which later independently evolved these traits

Verreaux’s sifaka was once a common lemur species across the south of Madagascar, but is now listed as critically endangered, the last classification before extinction

Verreaux’s sifaka was once a common lemur species across the south of Madagascar, but is now listed as critically endangered, the last classification before extinction

A 13,000-year-old mammoth tusk has engravings of camels fighting and being hunted, plus an image of a human with a camel’s hump on their body

A 13,000-year-old mammoth tusk has engravings of camels fighting and being hunted, plus an image of a human with a camel’s hump on their body

A 13,000-year-old mammoth tusk has engravings of camels fighting and being hunted, plus an image of a human with a camel’s hump on their body

The “bystander effect” can influence humans – and now it seems rats as well – not to step in to help another, but only if the bystanders are emotionally uninterested in what is happening

The “bystander effect” can influence humans – and now it seems rats as well – not to step in to help another, but only if the bystanders are emotionally uninterested in what is happening

The “bystander effect” can influence humans – and now it seems rats as well – not to step in to help another, but only if the bystanders are emotionally uninterested in what is happening

There are lots of claims that house plants filter the air, but it turns out you need an awful lot of them to beat just opening the window, finds James Wong

There are lots of claims that house plants filter the air, but it turns out you need an awful lot of them to beat just opening the window, finds James Wong