An international team of researchers with the participation of experts from the Higher Council for Scientific Research (CSIC) has managed to generate an infective clone of SARS-CoV-2 from the use of artificial bacterial chromosomes.

As explained by the CSIC, It is “a fundamental tool” to study the coronavirus, since will allow to know essential details of the viral cycle and to develop new antiviral treatments and vaccines live attenuated. The work, published in the magazine mBio, and part of the use of bacterial artificial chromosomes for the generation of a stable infective clone of SARS-CoV-2.

Directed by Luis Martínez-Sobrido, researcher at the Texas Institute for Biomedical Research in the United States, in the study too they participated scientists Fernando Almazán, from the National Center for Biotechnology (CNB-CSIC), and Juan Carlos de la Torre, from the Scripps Research Institute of San Diego (La Joya, United States).

Success in other coronaviruses and Zika

“The generation of infective clones of viruses belonging to the coronavirus family presents several technical difficulties due to the large size of the viral genome and the toxicity of some of its sequences when they are amplified in bacteria “, explained Fernando Almazán.

“For this reason, the use of bacterial artificial chromosomes was resorted to for the generation of a stable infective clone of SARS-CoV-2, since” these plasmids allow cloning of large exogenous sequences and minimize toxicity problems. ” had already been applied with success to generate infective clones from other coronaviruses and other viruses like Zika. “

From synthetic DNA fragments that span the entire genome of the virus, the new system generates a DNA copy of the viral genome that assembles on the bacterial artificial chromosome under the control of a promoter recognized by the cellular machinery. The infective clone thus created is introduced into the cell, where it is transcribed by the cellular machinery, generating copies of the viral genome that initiate the cycle of infection and give rise to infectious viral particles.

“A powerful tool”

The researchers checked the stability of the virus produced and the effects of the infection on hamsters, where they observed that the pathogenicity and infective capacity is similar to that of the original virus.

According to the authors, these clones are “A powerful tool to know details of the biology of SARS-CoV-2, such as which are the cellular factors that the virus needs in its expansion ”.

In turn, this will make it easier to identify targets. therapeutic, analyze the effectiveness of new antivirals and facilitate the development of live attenuated vaccines “.