Month: September 2022

FUNCTIONAL HERV LTRs. "The vast majority of these HERV elements are presumably not infectious or functional, but there are numerous reports on the expression of endogenous retroviral transcripts in human tissues and cell lines, mostly of placental, embryonic, or neoplastic origin. This suggests that a considerable number of HERV LTRs have retained their transcriptional activity." http://jvi.asm.org/content/79/1/341.full View in LinkedIn

SILENCED. "Transcription of HERV-K and other HERV elements is usually suppressed by epigenetic factors such as DNA methylation and heterochromatin-silencing by histone modifications. During tumorigenesis (and also, presumably, in other poorly understood situations) this epigenetic control can be partially or selectively weakened and particular retroviral promoters become able to vigorously activate the transcription of cellular genes." http://journal.frontiersin.org/article/10.3389/fonc.2013.00246/full View in LinkedIn

SPECIALIZED HERVs. "There is evidence that transcription of at least some HERV families may be differentially regulated depending on the cell type." http://jvi.asm.org/content/79/1/341.full View in LinkedIn

"ERVs belong to the class of retroelements possessing the three viral genes group-specific antigen (gag), polymerase (pol) and envelope (env) flanked by two long terminal repeats (LTR). Deletions and mutations resulted in inactivation of most of the 400,000 ERV copies, but some sustained an intact open reading frame and are able to express ERV sequences on RNA and protein level. In the majority of cases ERVs will be expressed tissue specific." https://lnkd.in/e8X7a46 View in LinkedIn

THE EVOLUTION OF THE PLACENTA and the implantation of a fetus changed the course of biology by permitting the emergence of mammals. Perhaps less known is the fact that this would never have occurred were it not for viral genes that got embedded into the genome early in the development of animals. View in LinkedIn

RECEPIE FOR MAN. "The human genome is a holobiontic union of the mammalian nuclear genome, the mitochondrial genome and large numbers of endogenized retroviral genomes." https://lnkd.in/eVHsFRU View in LinkedIn

FIRST GIANT JUMP. "The human genome has experienced two distinct rounds of holobiontic evolutionary change. The first of these involved the incorporation of the bacterial symbiont that gave rise to our human mitochondria, enabling us to breathe oxygen." https://lnkd.in/ecEx-Mq View in LinkedIn

SECOND GIANT JUMP. "The second involved the incorporation of a large series of retroviral genomes that have contributed to genomic evolution, embryology and adult physiology." http://onlinelibrary.wiley.com/doi/10.1111/apm.12488/full View in LinkedIn

"THE INVENTION OF THE PLACENTA facilitated the evolution of mammals. How the placenta evolved from the simple structure observed in birds and reptiles into the complex organ that sustains human life is one of the great mysteries of evolution." https://lnkd.in/eN_bZTg View in LinkedIn

APPEARANCE OF THE PLACENTA. "Over 120 million years ago, eutherian mammals appeared on the earth. Their appearance was dependent on the evolution of the placenta, which, by mediating nutrient and gas exchange between mother and fetus, serves the central role in bearing live offspring." https://lnkd.in/eN_bZTg View in LinkedIn