Endogenous bornavirus-like nucleoprotein elements (EBLNs) are DNA sequences in vertebrate genomes formed by the retrotransposon-mediated integration of ancient bornavirus sequence. Thus, EBLNs evidence a mechanism of retrotransposon-mediated RNA-to-DNA information flow from environment to animals. Although EBLNs are non-transposable, they share some features with retrotransposons. Here, to test...

Retrotransposons are major components of plant and animal genomes. They amplify by reverse transcription and reintegration into the host genome but their activity is usually epigenetically silenced. In plants, genomic copies of retrotransposons are typically associated with repressive chromatin modifications installed and maintained by RNA-directed DNA methylation. To escape this tight control,...

Previous studies suggested that the aryl hydrocarbon receptor (AhR) contributes to mice reproduction and fertility. However, the mechanisms involved remain mostly unknown. Retrotransposon silencing by Piwi-interacting RNAs (piRNAs) is essential for germ cell maturation and, remarkably, AhR has been identified as a regulator of murine B1-SINE retrotransposons. Here, using littermate AhR+/+ and A...

We analyzed the distribution of 54 families of transposable elements (TEs; transposons, LTR retrotransposons, and non-LTR retrotransposons) in the chromosomes of Drosophila melanogaster, using data from the sequenced genome. The density of LTR and non-LTR retrotransposons (RNA-based elements) was high in regions with low recombination rates, but there was no clear tendency to parallel the recom...

A novel family of tRNA-related SINEs named gecko was discovered in the yellow fever mosquito, Aedes aegypti. Approximately 7200 copies of gecko were distributed in the A. aegypti genome with a significant bias toward A + T-rich regions. The 3' end of gecko is similar in sequence and identical in secondary structure to the 3' end of MosquI, a non-LTR retrotransposon in A. aegypti. Nine conserved...

Long terminal repeat retrotransposons (LTR) are widespread in vertebrates and their dynamism facilitates genome evolution. However, these endogenous retroviruses (ERVs) must be restricted to maintain genomic stability. The APOBECs, a protein family that can edit C-to-U in DNA, do so by interfering with reverse transcription and hypermutating retrotransposon DNA. In some cases, a retrotransposon...

The acquisition of multiple genes from long terminal repeat (LTR) retrotransposons occurred in mammals. Genes belonging to a sushi-ichi-related retrotransposon homologs (SIRH) family emerged around the time of the establishment of two viviparous mammalian groups, marsupials and eutherians. These genes encode proteins that are homologous to a retrotransposon Gag capsid protein and sometimes also...

Transposable elements (TEs) make up around 10%-15% of the Drosophila melanogaster genome, but its sibling species Drosophila simulans carries only one third as many such repeat sequences. We do not, however, have an overall view of copy numbers of the various classes of TEs (long terminal repeat [LTR] retrotransposons, non-LTR retrotransposons, and transposons) in genomes of natural populations...

The gypsy group of long-terminal-repeat retrotransposons contains elements having the same order of enzyme domains in the pol gene as do retroviruses. Elements in the gypsy group are now known from yeast, filamentous fungi, plants, insects, and echinoids. Reverse transcriptase and RNase H amino acid sequences from elements in the gypsy group--including the recently described SURL elements, TED,...

The AID / APOBEC genes are a family of cytidine deaminases that have evolved in vertebrates, and particularly mammals, to mutate RNA and DNA at distinct preferred nucleotide contexts (or "hotspots") on foreign genomes such as viruses and retrotransposons. These enzymes play a pivotal role in intrinsic immunity defense mechanisms, often deleteriously mutating invading retroviruses or retrotransp...