Biomaterial Database

ALV Integration-Associated Hypomethylation at the TERT Promoter Locus. 2018

Gary Lam, and Karen Beemon

Department of Biology, Johns Hopkins University, Baltimore MD 21218, USA. glam5@jhu.edu.

Avian leukosis virus (ALV) is a simple retrovirus that can induce B-cell lymphoma in chicken(s) and other birds by insertional mutagenesis. The promoter region of telomerase reverse transcriptase (TERT) has been identified as an important integration site for tumorigenesis. Tumors with TERT promoter integrations are associated with increased TERT expression. The mechanism of this activation is still under investigation. We asked whether insertion of proviral DNA perturbs the epigenome of the integration site and, subsequently, impacts the regulation of neighboring genes. DNA cytosine methylation, which generally acts to suppress transcription, is one major form of epigenetic regulation. In this study, we examine allele-specific methylation patterns of genomic DNA from chicken tumors by bisulfite sequencing. We observed that alleles with TERT promoter integrations are associated with decreased methylation in the host genome near the site of integration. Our observations suggest that insertion of ALV in the TERT promoter region may induce expression of TERT through inhibition of maintenance methylation in the TERT promoter region.

UI	MeSH Term	Description	Entries
D011401	Promoter Regions, Genetic	DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.	rRNA Promoter,Early Promoters, Genetic,Late Promoters, Genetic,Middle Promoters, Genetic,Promoter Regions,Promoter, Genetic,Promotor Regions,Promotor, Genetic,Pseudopromoter, Genetic,Early Promoter, Genetic,Genetic Late Promoter,Genetic Middle Promoters,Genetic Promoter,Genetic Promoter Region,Genetic Promoter Regions,Genetic Promoters,Genetic Promotor,Genetic Promotors,Genetic Pseudopromoter,Genetic Pseudopromoters,Late Promoter, Genetic,Middle Promoter, Genetic,Promoter Region,Promoter Region, Genetic,Promoter, Genetic Early,Promoter, rRNA,Promoters, Genetic,Promoters, Genetic Middle,Promoters, rRNA,Promotor Region,Promotors, Genetic,Pseudopromoters, Genetic,Region, Genetic Promoter,Region, Promoter,Region, Promotor,Regions, Genetic Promoter,Regions, Promoter,Regions, Promotor,rRNA Promoters
D011533	Proviruses	Duplex DNA sequences in eukaryotic chromosomes, corresponding to the genome of a virus, that are transmitted from one cell generation to the next without causing lysis of the host. Proviruses are often associated with neoplastic cell transformation and are key features of retrovirus biology.	Provirus
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D002642	Chick Embryo	The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.	Embryo, Chick,Chick Embryos,Embryos, Chick
D000483	Alleles	Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.	Allelomorphs,Allele,Allelomorph
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001354	Avian Leukosis Virus	The type species of ALPHARETROVIRUS producing latent or manifest lymphoid leukosis in fowl.	Leukosis Virus, Avian,Lymphomatosis Virus, Avian,Rous-Associated Virus,Avian Leukosis Viruses,Avian Lymphomatosis Virus,Avian Lymphomatosis Viruses,Leukosis Viruses, Avian,Lymphomatosis Viruses, Avian,Rous Associated Virus,Virus, Avian Leukosis,Virus, Avian Lymphomatosis,Virus, Rous-Associated,Viruses, Avian Leukosis,Viruses, Avian Lymphomatosis
D016662	Virus Integration	Insertion of viral DNA into host-cell DNA. This includes integration of phage DNA into bacterial DNA; (LYSOGENY); to form a PROPHAGE or integration of retroviral DNA into cellular DNA to form a PROVIRUS.	Integration, Provirus,Integration, Virus,Provirus Integration,Viral integration,Integrations, Provirus,Integrations, Virus,Provirus Integrations,Viral integrations,Virus Integrations,integration, Viral,integrations, Viral
D044127	Epigenesis, Genetic	A genetic process by which the adult organism is realized via mechanisms that lead to the restriction in the possible fates of cells, eventually leading to their differentiated state. Mechanisms involved cause heritable changes to cells without changes to DNA sequence such as DNA METHYLATION; HISTONE modification; DNA REPLICATION TIMING; NUCLEOSOME positioning; and heterochromatization which result in selective gene expression or repression.	Epigenetic Processes,Epigenetic Process,Epigenetics Processes,Genetic Epigenesis,Process, Epigenetic,Processes, Epigenetic,Processes, Epigenetics
D018899	CpG Islands	Areas of increased density of the dinucleotide sequence cytosine--phosphate diester--guanine. They form stretches of DNA several hundred to several thousand base pairs long. In humans there are about 45,000 CpG islands, mostly found at the 5' ends of genes. They are unmethylated except for those on the inactive X chromosome and some associated with imprinted genes.	CpG Clusters,CpG-Rich Islands,Cluster, CpG,Clusters, CpG,CpG Cluster,CpG Island,CpG Rich Islands,CpG-Rich Island,Island, CpG,Island, CpG-Rich,Islands, CpG,Islands, CpG-Rich