tRNA integrity is a prerequisite for rapid CCA addition: implication for quality control.

CCA addition to the 3' end is an essential step in tRNA maturation. High-resolution crystal structures of the CCA enzymes reveal primary enzyme contact with the tRNA minihelix domain, consisting of the acceptor stem and T stem-loop. RNA and DNA minihelices are efficient substrates for CCA addition in steady-state kinetics.

The dermal microenvironment induces the expression of the alternative activation marker CD301/mMGL in mononuclear phagocytes, independent of IL-4/IL-13 signaling.

Recently, we have shown that mononuclear phagocytes comprise the majority of interstitial cells in the mouse dermis, as indicated by their phenotypic and functional characteristics. In particular, these cells express the mouse macrophage galactose-/N-acetylgalactosamine-specific-lectin (mMGL)/CD301, identified by the monoclonal antibody ER-MP23, as well as other macrophage markers. As expression of mMGL is induced by IL-4 or IL-13 and is therefore a marker of alternatively activated macrophages, we asked whether dermal mononuclear phagocytes are genuinely alternatively activated.

Dendritic cells in vivo and in vitro.

Dendritic cells (DC) are crucial cells of the immune system, and bridge the essential connection between innate and adaptive immunity. They reside in the periphery as sentinels where they take up antigens. Upon activation, they migrate to lymphoid organs and present there the processed antigens to T cells, thereby activating them and eliciting a potent immune response.

Macrophages and dendritic cells constitute a major subpopulation of cells in the mouse dermis.

Macrophages and dendritic cells (DC) in tissues with close contact to the environment are of essential importance in host defense and are therefore present in sizeable numbers. Therefore, it is surprising that mononuclear phagocyte populations of the dermis have rarely been investigated in a quantitative manner. In this study, we examined mouse dermal skin immunophenotypically and related the observed numbers of observed cells to the total number of nucleated cells.

UBA1 and UBA2, two proteins that interact with UBP1, a multifunctional effector of pre-mRNA maturation in plants.

Nicotiana plumbaginifolia UBP1 is an hnRNP-like protein associated with the poly(A)(+) RNA in the cell nucleus. Consistent with a role in pre-mRNA processing, overexpression of UBP1 in N. plumabaginifolia protoplasts enhances the splicing of suboptimal introns and increases the steady-state levels of reporter mRNAs, even intronless ones.