Embryonic expression of endogenous retroviral RNAs in somatic tissues adjacent to the Oikopleura germline.
Bottom Line: Tor Env proteins are membrane-associated glycoproteins which exhibit some features of viral membrane fusion proteins.Such embryonic expression depends on determinants present in the Tor elements and not on their surrounding genomic environment.Our study shows that unusual modes of transcription and expression close to the germline may contribute to the proliferation of Tor elements.
Affiliation: Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, N-5008, Norway email@example.com.Show MeSH
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Mentions: To better understand the mechanisms by which Tor elements proliferate, we studied the expression of pol and env during development. We first tested for the presence of transcripts in cDNA samples prepared at successive developmental stages using RT-PCR and hybridizations on genome tiling arrays (23) (Figure 4B and Supplementary Figure S5C). Both techniques showed that for most elements, Tor RNA seemed to be absent or present in very low amounts during the first hours of development. Embryonic expression of Tor was first detected between 80 and 100 min pf, during early gastrulation (29) (Figure 4BB). On tiling arrays, we found that 29 out of 100 elements showed significant expression during tailbud and hatching stages (Figure 4BA). Among these, 13 elements were expressed only during embryogenesis, with the highest levels at tailbud or hatching stages. Other elements were expressed mainly after the larval tailshift. RT-PCR assays were in agreement with the tiling array data and for three Tor3b/4b elements we also confirmed the presence of gRNA and env mRNA in embryos (Figure 4BC). Expression profiling showed that for most Tor elements, increases in gene expression occurred during specific developmental stages. We next checked if Tor RNA is present in somatic tissues or in the germ line.
Affiliation: Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, N-5008, Norway firstname.lastname@example.org.