Biomaterial Database

Integration target site selection for retroviruses and transposable elements. 2004

X Wu, and S M Burgess

Laboratory of Molecular Technology, Scientific Application International Inc., National Cancer Institute at Frederick, 915 Tollhouse Ave., Frederick, Maryland 21701, USA.

When a retrovirus infects a cell, its RNA genome is reverse transcribed into a double-stranded DNA, which is then permanently integrated into the host chromosome. Integration is one of the essential steps in the retroviral life cycle. Many transposable elements also move around and integrate into the host genome as part of their life cycle, some through RNA intermediates and some through 'cut and paste' mechanisms. Integration of retroviruses and transposable elements into 'sensitive areas' of the genome can cause irreparable damage. On the other hand, because of their ability to integrate permanently, and the relatively efficient rates of transgenesis, retroviruses and transposable elements are widely used as gene delivery tools in basic research and gene therapy trials. Recent events in gene therapy treatments for X-linked severe combined immunity deficiencies (X-SCID) have highlighted both the promise and some of the risks involved with utilizing retroviruses. Nine of 11 children were successfully treated for X-SCID using a retrovirus carrying the gene mutated in this disease. However, later two of these children developed leukemias because of retroviral integrations in the putative oncogene LMO2 [1]. A third child has also been demonstrated to have an integration in LMO2, but is as of yet nonsymptomatic [2]. It is a bit difficult to explain the high frequency of integrations into the same gene using a random model of retroviral integration, and there has been evidence for decades that retroviral integrations may not be random. But the data were somewhat limited in their power to determine the precise nature of the integration biases. The completion of the human genome sequence coupled with sensitive polymerase chain reaction techniques and an ever-decreasing cost of sequencing has given a powerful new tool to the study of integration site selection. In this review, we describe the findings from several recent global surveys of target site selection by retroviruses and transposable elements, and discuss the possible ramifications of these findings to both mechanisms of action and to the use of these elements as gene therapy vectors.

UI	MeSH Term	Description	Entries
D009052	Leukemia Virus, Murine	Species of GAMMARETROVIRUS, containing many well-defined strains, producing leukemia in mice. Disease is commonly induced by injecting filtrates of propagable tumors into newborn mice.	Graffi Virus,Graffi's Chloroleukemic Strain,Leukemia Viruses, Murine,Mouse Leukemia Viruses,Murine Leukemia Virus,Murine Leukemia Viruses,Graffi Chloroleukemic Strain,Graffis Chloroleukemic Strain,Leukemia Viruses, Mouse
D004251	DNA Transposable Elements	Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.	DNA Insertion Elements,DNA Transposons,IS Elements,Insertion Sequence Elements,Tn Elements,Transposable Elements,Elements, Insertion Sequence,Sequence Elements, Insertion,DNA Insertion Element,DNA Transposable Element,DNA Transposon,Element, DNA Insertion,Element, DNA Transposable,Element, IS,Element, Insertion Sequence,Element, Tn,Element, Transposable,Elements, DNA Insertion,Elements, DNA Transposable,Elements, IS,Elements, Tn,Elements, Transposable,IS Element,Insertion Element, DNA,Insertion Elements, DNA,Insertion Sequence Element,Sequence Element, Insertion,Tn Element,Transposable Element,Transposable Element, DNA,Transposable Elements, DNA,Transposon, DNA,Transposons, DNA
D005822	Genetic Vectors	DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.	Cloning Vectors,Shuttle Vectors,Vectors, Genetic,Cloning Vector,Genetic Vector,Shuttle Vector,Vector, Cloning,Vector, Genetic,Vector, Shuttle,Vectors, Cloning,Vectors, Shuttle
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000229	Dependovirus	A genus of the family PARVOVIRIDAE, subfamily PARVOVIRINAE, which are dependent on a coinfection with helper adenoviruses or herpesviruses for their efficient replication. The type species is Adeno-associated virus 2.	Adeno-Associated Viruses,Dependoparvovirus,Adeno-Associated Virus,Virus, Adeno-Associated,Viruses, Adeno-Associated,Adeno Associated Virus,Adeno Associated Viruses,Dependoparvoviruses,Dependoviruses,Virus, Adeno Associated,Viruses, Adeno Associated
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
D012190	Retroviridae	Family of RNA viruses that infects birds and mammals and encodes the enzyme reverse transcriptase. The family contains seven genera: DELTARETROVIRUS; LENTIVIRUS; RETROVIRUSES TYPE B, MAMMALIAN; ALPHARETROVIRUS; GAMMARETROVIRUS; RETROVIRUSES TYPE D; and SPUMAVIRUS. A key feature of retrovirus biology is the synthesis of a DNA copy of the genome which is integrated into cellular DNA. After integration it is sometimes not expressed but maintained in a latent state (PROVIRUSES).	Leukemogenic Viruses,Leukoviruses,Oncornaviruses,Oncovirinae,Oncoviruses,Oncoviruses, Type C,RNA Tumor Viruses,Retroviruses,Type C Oncoviruses,C Oncovirus, Type,C Oncoviruses, Type,Leukemogenic Virus,Leukovirus,Oncornavirus,Oncovirus,Oncovirus, Type C,RNA Tumor Virus,Retrovirus,Tumor Virus, RNA,Tumor Viruses, RNA,Type C Oncovirus,Virus, Leukemogenic,Virus, RNA Tumor,Viruses, Leukemogenic,Viruses, RNA Tumor
D015368	Human T-lymphotropic virus 1	A strain of PRIMATE T-LYMPHOTROPIC VIRUS 1 isolated from mature T4 cells in patients with T-lymphoproliferation malignancies. It causes adult T-cell leukemia (LEUKEMIA-LYMPHOMA, T-CELL, ACUTE, HTLV-I-ASSOCIATED), T-cell lymphoma (LYMPHOMA, T-CELL), and is involved in mycosis fungoides, SEZARY SYNDROME and tropical spastic paraparesis (PARAPARESIS, TROPICAL SPASTIC).	ATLV,Adult T-Cell Leukemia-Lymphoma Virus I,HTLV-1,HTLV-I,Human T-Cell Leukemia Virus I,Leukemia Virus I, Human T-Cell,T-Cell Leukemia Virus I, Human,Adult T Cell Leukemia Lymphoma Virus I,Human T Cell Leukemia Virus I,Leukemia Lymphoma Virus I, Adult T Cell,Leukemia Virus I, Human T Cell,T Cell Leukemia Virus I, Human,Human T lymphotropic virus 1
D015497	HIV-1	The type species of LENTIVIRUS and the etiologic agent of AIDS. It is characterized by its cytopathic effect and affinity for the T4-lymphocyte.	Human immunodeficiency virus 1,HIV-I,Human Immunodeficiency Virus Type 1,Immunodeficiency Virus Type 1, Human
D016511	Severe Combined Immunodeficiency	Group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. It is inherited as an X-linked or autosomal recessive defect. Mutations occurring in many different genes cause human Severe Combined Immunodeficiency (SCID).	Bare Lymphocyte Syndrome,Immunodeficiency, Severe Combined,Omenn Syndrome,Immunodeficiency Syndrome, Severe Combined,Immunologic Deficiency, Severe Combined,Omenn's Syndrome,Reticuloendotheliosis, Familial,Severe Combined Immune Deficiency,Severe Combined Immunodeficiency Syndrome,Severe Combined Immunologic Deficiency,Bare Lymphocyte Syndromes,Combined Immunodeficiencies, Severe,Combined Immunodeficiency, Severe,Familial Reticuloendothelioses,Familial Reticuloendotheliosis,Immunodeficiencies, Severe Combined,Lymphocyte Syndrome, Bare,Lymphocyte Syndromes, Bare,Omenns Syndrome,Reticuloendothelioses, Familial,Severe Combined Immunodeficiencies,Syndrome, Bare Lymphocyte,Syndrome, Omenn,Syndrome, Omenn's,Syndromes, Bare Lymphocyte