The effects of four environmental stresses of heat, drought, wounding and cell culture, on the transcriptional reactivation of seven long terminal repeat retrotransposons (LTRs) of barley (Hordeum vulgare) genome, were investigated. These LTRs included two Copia-type (Bare and Maximus); and five Gypsy-type (Erika, Jeli, Sabrina, Sukkula1 and Sukkula3) LTRs. RT-qPCR analyses revealed that Erika1...

Mouse mammary tumor virus (MMTV) is transcribed at high levels in the lactating mammary gland to ensure transmission of virus from the milk of infected female mice to susceptible offspring. We previously have shown that the transcription factor CCAAT displacement protein (CDP) is expressed in high amounts in virgin mammary gland, yet DNA-binding activity for the MMTV long terminal repeat (LTR) ...

Mobile elements that use reverse transcriptase to make new copies of themselves are found in all major lineages of eukaryotes. The non-long terminal repeat (non-LTR) retrotransposons have been suggested to be the oldest of these eukaryotic elements. Phylogenetic analysis of non-LTR elements suggests that they have predominantly undergone vertical transmission, as opposed to the frequent horizon...

BACKGROUND Episomal 2-long terminal repeat (LTR) HIV-1 cDNA, a by-product of HIV-1 infection, is used in clinical trials as a marker for ongoing viral replication. It would be useful to employ 2-LTR cDNA to monitor cryptic HIV-1 infection in the genital tract of men on antiretroviral therapy (ART) to predict the evolution of sexually transmissible drug-resistant HIV-1, but studies thus far have...

Delivering attenuated lentivirus vaccines as proviral DNA would be simple and inexpensive. Inoculation of macaques with wild-type simian immunodeficiency virus strain mac239 (SIV(mac239)) DNA or SIV(mac239) DNA containing a single deletion in the 3' nef-long terminal repeat overlap region (nef/LTR) led to sustained SIV infections and AIDS. Injection of SIV(mac239) DNA containing identical delet...

Transcriptional activation of the HIV type 1 (HIV-1) long terminal repeat (LTR) promoter element by the viral Tat protein is an essential step in the HIV-1 life cycle. Tat function is mediated by the TAR RNA target element encoded within the LTR and is known to require the recruitment of a complex consisting of Tat and the cyclin T1 (CycT1) component of positive transcription elongation factor ...

In a broad range of taxa, genes can duplicate through an RNA intermediate in a process mediated by retrotransposons (retroposition). In mammals, L1 retrotransposons drive retroposition, but the elements responsible for retroposition in other animals have yet to be identified. Here, we examined young retrocopies from various animals that still retain the sequence features indicative of the under...

Simian foamy viruses, members of the spumavirus subfamily of retroviruses, are found in a variety of nonhuman primates and, as yet, remain to be characterized with respect to genetic structure and regulation of viral gene expression. The genome of simian foamy virus type 1 (SFV-1), an isolate from rhesus macaques, has been molecularly cloned, and the role of the viral long terminal repeat (LTR)...

The proto-oncogene c-myb encodes a nuclear transcription factor that binds to DNA in a sequence-specific manner and activates transcription of several viral and cellular genes. Expression of the c-myb gene is induced in mitogen- and/or antigen-stimulated T lymphocytes, which are also the preferential target cells of human T-lymphotropic virus type I (HTLV-I) in vivo and in vitro. We report here...

Ty3/Gypsy long terminals repeat (LTR) retrotransposons are structurally and phylogenetically close to retroviruses. Two notable structural differences between these groups of genetic elements are 1) the presence in retroviruses of an additional envelope gene, env, which mediates infection, and 2) a specific dual ribonuclease H (RNH) domain encoded by the retroviral pol gene. However, similar to...