PIWI-interacting RNAs (piRNAs) protect the germ line by targeting transposable elements (TEs) through the base-pair complementarity. We do not know how piRNAs co-evolve with TEs in chickens. Here we reported that all active TEs in the chicken germ line are targeted by piRNAs, and as TEs lose their activity, the corresponding piRNAs erode away. We observed de novo piRNA birth as host responds to...

3H-Labeled complementary DNA specific for the envelope glycoprotein (env) gene of avian leukosis-sarcoma viruses was isolated by selective nucleic acid hybridization techniques, and used to analyze the expression of the endogenous provirus. The endogenous provirus in certain cell types termed chicken helper factor positive (chf+) can synthesize the envelope glycoprotein. Env DNA sequences were ...

Disease can be an important driver of host population dynamics and epizootics can cause severe host population declines. Batrachochytrium dendrobatidis (Bd), the pathogen causing amphibian chytridiomycosis, may occur epizootically or enzootically and can harm amphibian populations in many ways. While effects of Bd epizootics are well documented, the effects of enzootic Bd have rarely been descr...

To date, the vast majority of known virus-encoded microRNAs (miRNAs) are derived from polymerase II transcripts encoded by DNA viruses. A recent demonstration that the bovine leukemia virus, a retrovirus, uses RNA polymerase III to directly transcribe the pre-miRNA hairpins to generate viral miRNAs further supports the common notion that the canonical pathway of miRNA biogenesis does not exist ...

The authors describe the history of enzootic bovine leukosis (EBL) in Estonia, including the occurrence and distribution of disease within the cattle population, and the factors which have influenced disease spread since the 1950s. The principles of various control schemes which were applied from 1960 to 1994 are also surveyed. Considerable progress in eradicating EBL has been achieved during r...

Antibodies against bovine leukaemia virus were detected in 322 of 1,511 serum samples from cattle of various age groups and both sexes, in various herds of the country. A variable degree (5.4 to 75%) of positive reactors was recorded in individual herds where no systematic breeding policy had been followed. Antibodies were also detected in clinically healthy cattle, having normal haematological...

To investigate the role of proviral integration and expression in cellular transformation induced by bovine leukemia virus (BLV), three BLV-induced tumors harboring a single proviral copy were selected upon restriction and hybridization analysis. Tumors 344 and 395 were shown to contain a full-size proviral copy, whereas in tumor 1345 the provirus appeared to be heavily deleted. RNA gel blot hy...