A highly efficient system to produce infectious human papillomavirus: Elucidation of natural virus-host interactions.

A simple, efficient system has been developed to produce high titers of infectious human papillomavirus type 18 (HPV-18) in organotypic raft cultures of primary human keratinocytes (PHKs). Molecular characterization elucidated key early and late events in the reproductive program. The system obviates the need for immortalized cells and allows the analyses of mutant HPV genomes not previously possible.

Robust production and passaging of infectious HPV in squamous epithelium of primary human keratinocytes.

Using Cre-loxP-mediated recombination, we established a highly efficient and reproducible system that generates autonomous HPV-18 genomes in primary human keratinocytes (PHKs), the organotypic raft cultures of which recapitulated a robust productive program. While E7 promoted S-phase re-entry in numerous suprabasal differentiated cells, HPV DNA unexpectedly amplified following a prolonged G2 arrest in mid- and upper spinous cells. As viral DNA levels intensified, E7 activity diminished and then extinguished.

Transcriptional regulation of the AT1 receptor gene in immortalized human trophoblast cells.

Studies investigating the mechanisms that govern the expression of the human angiotensin II (Ang II) type 1 receptor (hAT1R) gene have progressed slowly due to the lack of human cell lines that express the AT1R. Recently, however, an immortalized human trophoblast cell line (HTR-8/SVNeo) was demonstrated to respond to Ang II. Therefore, we utilized this cell line to characterize the AT1R expressed on the cell surface and to investigate the mechanisms by which the hAT1R gene is regulated in these cells.

Translation of the human angiotensin II type 1 receptor mRNA is mediated by a highly efficient internal ribosome entry site.

Activation of the angiotensin II type 1 receptor (AT1R) is closely involved in the pathogenesis of cardiovascular disease. The human AT1R (hAT1R) mRNA splice variants have long 5'-untranslated regions (5'-UTRs) ranging from 272 to 414 bp that have the potential to form stable secondary structures. In this study, we show that the 5'-UTR of hAT(1)R mRNAs contains an internal ribosome entry site (IRES) located within the first 40 bp of the proximal end of exon 1.