NR AWJK
AU Malaga-Trillo,E.; Solis,G.P.; Luncz,L.; Schrock,Y.; Stuermer,C.A.O.
TI Conserved roles of vertebrate prion proteins I
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions GEN-17
PT Konferenz-Poster
AB Contrary to the wealth of information available on prion pathogenesis, the natural role of PrP remains a largely unsolved issue. For the last 14 years, it has been difficult to approach this question due to the lack of visible phenotypes in PrP knockout mice. To overcome this problem, we performed loss- and -gain-of-function analyses in the zebrafish using a combination of developmental techniques including morpholino knockdown and RNA overexpression of various full-length and deletion PrP fluorescent constructs in wild type and transgenic zebrafish. We have shown that knockdown of zebrafish PrPs produces strong developmental loss-of-function phenotypes, which can be rescued by fish and mammalian PrPs. In order to uncover the molecular and cellular mechanisms behind this conserved function, we carried out a closer analysis of our PrP phenotypes. We observe that lack of PrP-1 results in early and lethal disruption of embryonic cell adhesion, causing developmental arrest at the onset of gastrulation; PrP-2 depletion impairs proliferation and differentiation of cranial neurons, along with a general effect on brain morphogenesis. Strong localization of fluorescently labeled PrPs to embryonic cell-cell contacts is in line with our data showing that PrP homotypic trans-interactions are sufficient to induce cell adhesion and signaling in mammalian and insect cells (see abstract by Solis et al.). We also assessed the relative contributions of PrP domains to its function during zebrafish embryogenesis. Proper PrP localization and embryonic cell adhesion (seen as the ability to rescue the PrP-1 phenotype) are affected to a larger degree by deletion of the globular domain than by deletion of the less conserved repetitive domain, indicating a stronger requirement of the former. This is in contrast to previous data postulating an essential role of the repetitive domain PrP in copper metabolism. Altogether, our experiments indicate that PrPs are required at embryonic cell contacts in order to mediate proper cell adhesion during gastrulation, as well as neuronal proliferation and differentiation. Thus, the evolutionarily conserved interaction between PrPs constitutes a positive and important signal for the cell, which may be lost or deregulated upon PrP conversion. Supported by the DFG, TR-SFB11, TSE-BW.
AD Department of Biology, University of Konstanz, 78457 Konstanz, Germany. E-mail: Edward.Malaga@uni-konstanz.de
SP englisch
PO Italien