The hematopoietic stem cell (HSC) compartment is composed of long-term reconstituting (LTR) and short-term reconstituting (STR) stem cells. LTR HSC can reconstitute the hematopoietic system for life, whereas STR HSC can sustain hematopoiesis for only a few weeks in the mouse. Several excellent gene expression profiles have been obtained of the total hematopoietic stem cell population. We have u...

G-quadruplexes are four-stranded conformations of nucleic acids that act as cellular epigenetic regulators. A dynamic G-quadruplex forming region in the HIV-1 LTR promoter represses HIV-1 transcription when in the folded conformation. This activity is enhanced by nucleolin, which induces and stabilizes the HIV-1 LTR G-quadruplexes. In this work by a combined pull-down/mass spectrometry approach...

Early during retroviral infection, a fraction of the linear reverse-transcribed viral DNA genomes become circularized by cellular enzymes, thereby inactivating the genomes for further replication. Prominent circular DNA forms include 2-long-terminal repeat (LTR) circles, made by DNA end joining, and 1-LTR circles, produced in part by homologous recombination. These reactions provide a convenien...

HIV-infected individuals currently cannot be completely cured because existing antiviral therapy regimens do not address HIV provirus DNA, flanked by long terminal repeats (LTRs), already integrated into host genome. Here, we present a possible alternative therapeutic approach to specifically and directly mediate deletion of the integrated full-length HIV provirus from infected and latently inf...

To understand long terminal repeat (LTR)-retrotransposon copy number dynamics, Ty1 elements were reintroduced into a "Ty-less" Saccharomyces strain where elements had been lost by LTR-LTR recombination. Repopulated strains exhibited alterations in chromosome size that were associated with Ty1 insertions, but did not become genetically isolated. The rates of element gain and loss under genetic a...

MOTIVATION Long terminal repeat (LTR) retrotransposons constitute a substantial fraction of most eukaryotic genomes and are believed to have a significant impact on genome structure and function. Conventional methods used to search for LTR retrotransposons in genome databases are labor intensive. We present an efficient, reliable and automated method to identify and analyze members of this impo...

The human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) represents a model promoter system and the identification and characterisation of cellular proteins that interact with this region has provided a basic understanding about both general eukaryotic and HIV-1 proviral transcriptional regulation. To date a large number of sequence-specific DNA-protein interactions have been ...

To investigate the role of Rac1 for tumorigenesis, we generated inducible transgenic (Tg) mice that simultaneously express polyomavirus middle T antigen (mT) and Cre recombinase under the control of mouse mammary tumor virus long terminal repeat (MMTV-LTR) promoter (MMTV-LTR-tTA/mT-TRE-cre Tg). MMTV-LTR-tTA/mT- TRE-cre Tg mice formed tumors in the subcutaneous tissue and developed lung metastas...

When Vero or murine cells were stably transfected with the human immunodeficiency virus (HIV) long terminal repeat (LTR) that directs the chloramphenicol acetyltransferase (CAT) gene (pU3R-III-CAT), expression was suppressed. Treatment with the nucleoside analog 5-azacytidine (5-azaC) restored CAT expression. S1 nuclease analysis and a nuclear run-on assay demonstrated that activation of the la...

A recombinant plasmid carrying the long terminal repeat (LTR) of the human immunodeficiency virus 1 (HIV-1) linked to the reporter chloramphenicol acetyl transferase (CAT) gene was stably introduced into human fibroblasts. The transfectant cells expressed CAT activity from the HIV LTR. The response to anti-neoplastic drugs, i.e. cisplatin, a platin derivative, and hexadecylphosphocholine, was s...