Paper on Cell by Tongji PhD Candidate Reveals How piRNA Responds to Retroviral Invasion of the Koala Genome

October 14, 2019

On October 10, 2019, a paper entitled "The piRNA Response to Retroiral Invasion of the Koala Genome" published on Cell by Guest Professor WENG Zhiping of Tongji University in conjunction with Professor William E. Theurkauf of School of Medicine, the University of Massachusetts, and Keith Chappell of the University of Queensland.

Antisense Piwi-interacting RNAs (piRNAs) are thought to be involved in gene silencing, specifically the silencing of transposons. The majority of piRNAs are antisense to transposon sequences, suggesting that transposons are the piRNA target. The transposon is a DNA sequence that can change its position within a genome, sometimes creating or reversing mutations and leading to multiple diseases. Most transposons were formed by virus invasion hundreds of thousands or even millions of years ago. We still do not know how germ cells respond to new virus invasion. Koala retrovirus (KoRV) is a gamma retrovirus that invades koalas in the past 200 to 40,000 years. It can transfer horizontally between individuals and vertically between parents and offspring. The virus is sweeping koalas across Australia. The "real-time" nature of KoRV invasion can help us study the genome's response to retroviral invasion.

In this paper, the genome and transcriptome of koalas invaded by KoRV were studied through high-throughput sequencing. Using a variety of histochemical sequence data, researchers annotated transposons in 402 koala genomes, including KoRV, and found that KoRV and three other retroviruses were actively expressed in koalas. By comparing the insertion sites of KoRV in different koala individuals, this paper confirms how KoRV invades different koala individuals in parallel and efficiently.

This study skillfully uses retroviruses that are invading the koala genome, discovers and confirms the response mechanism of reproductive system to virus invasion. It opens up new ideas for genome immune response and functional regulation, and has far-reaching influence and significance.

About the authors:

Yu, Tianxiong, Birgit Koppetsch, Keith Chappell, Sara Pagliarani, Stephen Johnston, Noah J. Silverstein, Jeremy Luban, Zhiping Weng, and William E. Thauerkauf. "The piRNA Response to Retroviral Invasion of the Koala Genome." CELL-D-19-01389 (2019).

YU Tianxiong, PhD candidate (since 2014) of Tongji university, and Birgit S. Koppetsch, research assistant from School of Medicine, the University of Massachusetts are the first authors of this paper. Professor WENG Zhiping of Tongji University, Professor William E. Theurkauf,School of Medicine, of the University of Massachusetts and Keith Chappell of the University of Queensland are the corresponding authors of this paper.

Full-text paper“The piRNA Response to Retrovical Invasion of the Koala Genome”is available at

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