We consistently demonstrate differences in epitope presentation kinetics, with very early presentation, within 3 h postinfection, for the protective KF11Gag, KK10Gag epitopes, and KY9Pol but only late presentation for VL9Vpr. We show that this early presentation relies on the antigen being presented from incoming viral particles and is correlated with rapid CD8(+) T cell activation and clearance of virus-infected cells. Additionally, our data indicate a dose-response dependency learn more between the levels of CD8(+) T cell activation and the amount of virus inoculum.
These data reflect a proof of principle emphasizing the importance of identifying early-presented viral epitopes for rapid elimination of HIV-1-infected cells.”
“The endosporic male gametophyte of the water fern, Marsilea vestita, provides a unique opportunity to study the mechanisms that control cell fate determination during a burst of rapid development. In this review, we show how the spatial and temporal control of development
in this simple gametophyte involves several distinct modes of RNA processing that allow the translation of specific mRNAs at distinct stages during gametogenesis. During the early part of development, nine successive cell division cycles occur in precise planes within a closed volume to see more produce seven sterile cells and 32 spermatids. There is no cell movement in the gametophyte; so, cell position and size within the spore wall define cell fate. After the division cycles have been completed, the spermatids become sites for the de novo formation of basal bodies, for the assembly of a complex cytoskeleton, for nuclear and cell elongation,
and for ciliogenesis. In contrast, the adjacent sterile cells exhibit none of these changes. Metalloexopeptidase The spermatids differentiate into multiciliated, corkscrew-shaped gametes that resemble no other cells in the entire plant. Development is controlled post-transcriptionally. The transcripts stored in the microspore are released (unmasked) in the gametophyte at different times during development. At the start of these studies, we identified several key mRNAs that undergo translation at specific stages of gametophyte development. We developed RNA silencing protocols that enabled us to block the translation of these proteins and thereby establish their necessity and sufficiency for the completion of specific stages of gametogenesis. In addition, RNAi enabled us to identify additional proteins that are essential for other phases of development. Since the distributions of mRNAs and the proteins they encode are not identical in the gametophyte, transcript processing is apparently important in allowing translation to occur under strict temporal and spatial control. Transcript polyadenylation occurs in the spermatogenous cells in ways that match the translation of specific mRNAs.