Project description:description Blastocystis sp. is a highly prevalent anaerobic eukaryotic parasite of humans and animals. The genome of several representatives has been sequenced revealing specific traits such as an intriguing 3’-end processing of primary transcripts. We have acquired a first high-throughput proteomics dataset on the difficult to cultivate ST4 isolate WR1 and detected 2,761 proteins. We evidenced for the first time by proteogenomics a functional termination codon derived from transcript polyadenylation for seven different key cellular components.
Project description:Despite intense investigation of intrinsic and extrinsic factors that regulate pluripotency, the process of initial fate commitment of embryonic stem (ES) cells is still poorly understood. Here, we used a genome wide shRNA screen in mouse ES cells to identify genes that are essential for initiation of differentiation. Knockdown of the scaffolding protein Mek binding protein 1 (Mp1, also known as Lamtor3, Map2k1ip1) stimulated self-renewal of ES cells, blocked differentiation and promoted proliferation. Fibroblast growth factor 4 (FGF4) signaling is required for initial fate commitment of ES cells. Knockdown of Mp1 inhibited FGF4-induced differentiation but did not alter FGF4 driven proliferation. This uncoupling of differentiation and proliferation was also observed when oncogenic Ras isoforms were over expressed in ES cells. Knockdown of Mp1 redirected FGF4 signaling from differentiation towards pluripotency and upregulated the pluripotency-related genes Esrrb, Rex1, Tcl1 and Sox2. We also found that human germ cell tumors express low amounts of Mp1 in the invasive embryonic carcinoma and seminoma histologies and higher amounts of Mp1 in the non-invasive carcinoma in situ precursor and differentiated components. Knockdown of Mp1 in invasive germ cell tumor cells resulted in resistance to differentiation, thereby showing a functional role for Mp1 both in normal differentiation of ES cells as well as in germ cell cancer.
