Scientists trace genes that aid and stem spread of the virus

NEWDELHI:USING the gene-editing tool CRISPR-CAS9, scientists have traced some of the genes that either aid or stem the spread of Sars-cov-2, which causes the coronavirus disease, in cells that were infected with the virus.

The screening of such genes, researchers say, can help them understand how the pathogen replicates in the human body, and point them towards potential treatments and vaccines that can target specific genes and cellular processes to stop the virus.

“Identification of host factors essential for infection is critical to inform mechanisms of Covid-19 pathogenesis, reveal variation in host susceptibility, and identify novel host-directed therapies, which may have efficacy against current and future pandemic coronaviruses,” found a study by researchers at the Yale School of Medicine and Broad Institute of MIT and Harvard in the US.

In the study, scientists snipped specific genes in cultured African green monkey cells – which are susceptible to Covid-19 – and infected those gene-edited cells with Sars-cov-2 to identify “pro viral” or “anti viral” genes.

The study, published as a preprint on Biorxiv on June 17, confirmed that the ACE2 receptor (angiotensin-converting enzyme 2) and Cathepsin L – proteins that were already believed to be crucial for the coronavirus’s entry into a host cell and its fusion with it – aided the virus in causing the infection.

Researchers also traced genes and pathways that assist the virus in replicating. These include a group of proteins that help package the DNA – called the SWI/SNF chromatin remodeling complex – and components of the TGF- (Transforming Growth Factor- Beta) signaling pathway, a family of proteins that plays a critical role in the growth of cells and their development.

The study, published on June 17 and yet to be peer reviewed, also found proteins called HMGB1, which can help activate the immune system, as “proviral”. Similarly, the study discovered that antiviral genes such as components in histones – proteins around which the DNA winds itself to fit into a cell nucleus – deterred the virus from replicating.

Scientists across the world are working round-the-clock to decode the workings of the Sarscov-2, but little is known about the pathogen. “Studying these will help us figure out how the cell is ‘trying’ to combat the virus,” John Doench, one of the authors of the study, tweeted last week.

MUMBAI: The lockdown may have brought neighbours closer, but for Matunga residents Varsha Padia and Varsha Shah, the love extended a lot further. One hot day in May, in the middle of the Covid-19 lockdown, they got down to work, kneading, rolling out, cooking and packing 60 theplas (flat breads) that would be delivered to the city’s stranded migrants and daily-wage labourers. A few days later, they prepared 68 more.

This is no mean feat. Padia is 70 and has been visually impaired for half her life. But she’s refused to get left behind, says Shah, 49, who lives next door and has known her for two decades. “She knows what’s happening in the world – news, films, events,” Shah said. So it’s no surprise that when Padia heard of a crowdsourced food relief initiative, both women jumped in to help. “We wanted to do something useful with our time,” said Padia. “And making large batches of food is not difficult; most Gujarati homes have 5 kg of flour at home at any given time.”

They divided their tasks, with Shah taking over the cooking, and their first round went smoothly. “We were done in just over an hour,” Padia said. With a little encouragement from Padia’s daughter, locked down in Juhu, a suburb of Mumbai further up north, the women repeated their contributions a few days later.

The thepla-making was part of a massive city-wide drive organised by the non-profit Circle of Love and Care.

The volunteer-run non-profit work is involved in activities as