Identification et caractérisation de deux facteurs d'épissage chez Trypanosoma brucei :modèle d'interactions impliquées dans le trans-épissage

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Identification et caractérisation de deux facteurs d'épissage chez Trypanosoma brucei :modèle d'interactions impliquées dans le trans-épissage

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

A ribosomal S12-like gene of Trypanosoma brucei.

Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Characterization of a Trypanosoma brucei SR domain-containing protein bearing homology to cis-spliceosomal U1 70 kDa proteins.

The protozoan parasite Trypanosoma brucei relies on trans-splicing of a common spliced leader (SL) RNA to maturate mRNAs. Using the yeast two-hybrid system a protein (TSR1IP) was identified that interacts with the T. brucei serine-arginine (SR) protein termed TSR1. TSR1IP shows homology to U1 70 kDa proteins, and contains an SR rich domain as well as an acidic/arginine domain homologous to the U1 70 kDa poly(A) polymerase inhibiting domain. This protein is localized in the nucleoplasm and excluded from the nucleolus in trypanosomal bloodstream and procyclic forms. Based on structural modelling predictions and on the identification of a RNA recognition motif (RRM), it was possible to demonstrate by the yeast three-hybrid system that TSR1IP interacts with the 5' splice region of the SL RNA. All the above characteristics suggest that TSR1IP could be involved in trans-splicing.Comparative StudyJournal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Characterization of a SR protein from Trypanosoma brucei with homology to RNA-binding cis-splicing proteins.

The protozoan parasite Trypanosoma brucei relies on trans-splicing to process its mRNAs. A novel nuclear serine/arginine (SR)-rich trypanosomal protein (TSR1) was characterized which contains two RNA recognition motifs. The TSR1 protein appears to be homologous to RNA-binding SR proteins of the cis-splicing machinery from higher eukaryotes. Moreover, in the yeast two-hybrid system, TSR1 is able to interact with the human splicing factors involved in the recognition of the 3' splicing site (U2AF35/U2AF65). In both procyclic and bloodstream forms of T. brucei, TSR1 was found to localize in the nucleus. In the bloodstream stage TSR1 showed the speckles pattern characteristic of SR proteins involved in cis-splicing. Moreover, TSR1 was able to specifically bind the spliced leader (SL) RNA involved in trans-splicing in trypanosomes by the yeast three-hybrid system. These and other observations suggest that TSR1 may be involved in trans-splicing in T. brucei.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Distinct VH repertoires in primary and secondary B cell lymphocyte subsets in the preimmune repertoire of A/J mice: The CRI-A idiotype is preferentially associated with the HSA(low) B cell subset

The anti-arsonate immune response of A/J mice is characterized by the occurrence of several recurrent idiotypes with a different temporal pattern of expression. The CRI-A idiotype is typically a memory idiotype since it appears late in the primary and dominates the secondary as well as subsequent immune responses. The CRI-C idiotype is present throughout the responses, including the primary one. Naive adult A/J mice treated repeatedly with anti-mu or anti-delta monoclonal antibodies exhibit a completely different balance of HSA(low) and HSA(high) B cell subsets and an opposite idiotype profile after immunization with p-azophenylarsonate coupled to hemocyanin. Anti-mu treatment leads to a striking enhancement of the HSA(low) cell subset associated with an earlier important synthesis of CRI-A(+) antibodies, while anti-delta treatment enhances significantly the HSA(high) compartment with a strong decrease of CRI-A and persistence of CRI-C1 antibodies. Semiquantitative PCR analysis reveals that the presence of CRI-A transcripts is associated with the HSA(low) compartment, while CRI-C transcripts are mainly associated with HSA(high) B cell subsets. This has been demonstrated with spleen cells of adult A/J mice treated with anti-mu or anti-delta antibodies and also with purified B cell subsets of unimmunized adult A/J mice and on neonatal spleen cells. It appears that the memory (CRI-A) idiotype is selected into the HSA(low) B cell subset before antigen arrival.FLWINSCOPUS: ar.jinfo:eu-repo/semantics/publishe