Selection for avian leukosis virus integration sites determines the clonal progression of B-cell lymphomas

PLoS Pathogens

Robin Morgan¹  Shelby Winans²  Gary Lam²  James Justice²  Karen Beemon²  Sanandan Malhotra² 

[1] Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America;Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America

关键词: DNA transcription;    Carcinogenesis;    DNA methylation;    Chickens;    Tissue cultures;    Gene expression;    Neoplasms;    B cells;   

DOI  :  10.1371/journal.ppat.1006708

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Avian leukosis virus (ALV) is a simple retrovirus that causes a wide range of tumors in chickens, the most common of which are B-cell lymphomas. The viral genome integrates into the host genome and uses its strong promoter and enhancer sequences to alter the expression of nearby genes, frequently inducing tumors. In this study, we compare the preferences for ALV integration sites in cultured cells and in tumors, by analysis of over 87,000 unique integration sites. In tissue culture we observed integration was relatively random with slight preferences for genes, transcription start sites and CpG islands. We also observed a preference for integrations in or near expressed and spliced genes. The integration pattern in cultured cells changed over the course of selection for oncogenic characteristics in tumors. In comparison to tissue culture, ALV integrations are more highly selected for proximity to transcription start sites in tumors. There is also a significant selection of ALV integrations away from CpG islands in the highly clonally expanded cells in tumors. Additionally, we utilized a high throughput method to quantify the magnitude of clonality in different stages of tumorigenesis. An ALV-induced tumor carries between 700 and 3000 unique integrations, with an average of 2.3 to 4 copies of proviral DNA per infected cell. We observed increasing tumor clonality during progression of B-cell lymphomas and identified gene players (especially TERT and MYB) and biological processes involved in tumor progression.

【 授权许可】

CC BY