TY  - JOUR
A1  - Fritz, Melanie
A1  - Vanselow, Jens
A1  - Sauer, Nadja
A1  - Lamer, Stephanie
A1  - Goos, Carina
A1  - Siegel, T. Nicolai
A1  - Subota, Ines
A1  - Schlosser, Andreas
A1  - Carrington, Mark
A1  - Kramer, Susanne
T1  - Novel insights into RNP granules by employing the trypanosome's microtubule skeleton as a molecular sieve
JF  - Nucleic Acids Research
N2  - RNP granules are ribonucleoprotein assemblies that regulate the post-transcriptional fate of mRNAs in all eukaryotes. Their exact function remains poorly understood, one reason for this is that RNP granule purification has not yet been achieved. We have exploited a unique feature of trypanosomes to prepare a cellular fraction highly enriched in starvation stress granules. First, granules remain trapped within the cage-like, subpellicular microtubule array of the trypanosome cytoskeleton while soluble proteins are washed away. Second, the microtubules are depolymerized and the granules are released.

RNA sequencing combined with single molecule mRNA FISH identified the short and highly abundant mRNAs encoding ribosomal mRNAs as being excluded from granules. By mass spectrometry we have identified 463 stress granule candidate proteins. For 17/49 proteins tested by eYFP tagging we have confirmed the localization to granules, including one phosphatase, one methyltransferase and two proteins with a function in trypanosome life-cycle regulation.

The novel method presented here enables the unbiased identification of novel RNP granule components, paving the way towards an understanding of RNP granule function.
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126180
ER  - 
TY  - JOUR
A1  - Siegel, T. Nicolai
A1  - Vasquez, Juan-José
A1  - Hon, Chung-Chau
A1  - Vanselow, Jens T.
A1  - Schlosser, Andreas
T1  - Comparative ribosome profiling reveals extensive translational complexity in different Trypanosoma brucei life cycle stages
N2  - While gene expression is a fundamental and tightly controlled cellular process that is regulated at multiple steps, the exact contribution of each step remains unknown in any organism. The absence of transcription initiation regulation for RNA polymerase II in the protozoan parasite Trypanosoma brucei greatly simplifies the task of elucidating the contribution of translation to global gene expression. Therefore, we have sequenced ribosome-protected mRNA fragments in T. brucei, permitting the genome-wide analysis of RNA translation and translational efficiency. We find that the latter varies greatly between life cycle stages of the parasite and ∼100-fold between genes, thus contributing to gene expression to a similar extent as RNA stability. The ability to map ribosome positions at sub-codon resolution revealed extensive translation from upstream open reading frames located within 5' UTRs and enabled the identification of hundreds of previously un-annotated putative coding sequences (CDSs). Evaluation of existing proteomics and genome-wide RNAi data confirmed the translation of previously un-annotated CDSs and suggested an important role for >200 of those CDSs in parasite survival, especially in the form that is infective to mammals. Overall our data show that translational control plays a prevalent and important role in different parasite life cycle stages of T. brucei.
KW  - Ribosom
KW  - Profilierung
KW  - Trypanosoma brucei
KW  - Entwicklung
KW  - Lebenszyklus
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-112657
ER  -