Project description:We used protein arrays to measure IgG2c autoantibodies associated with Connective Tissue Diseases (CTDs) from retrogenic chimeras Sera was isolated from irradiated Icos-/-;CD45.1 mice reconstituted with 564Igi;Icos-/- bone marrow mixed with Icos-/-;CD45.1 bone marrow and WT bone marrow (BMchim.564) or retrogenic HSCs expressing TCR-A (BMchim.564-Icos.RAG-TCRA), TCR-B (BMchim.564-Icos.RAG-TCRB), or TCR-C (BMchim.564-Icos.RAG-TCRC). 564Igi (564homo) and 564Igi;Icos-/- (564homo.Icos) sera were included as controls.
Project description:We used protein arrays to measure IgG2a autoantibodies associated with Connective Tissue Diseases (CTDs) from retrogenic chimeras Sera was isolated from irradiated Icos-/-;CD45.1 mice reconstituted with 564Igi;Icos-/- bone marrow mixed with Icos-/-;CD45.1 bone marrow and WT bone marrow (BMchim.564) or retrogenic HSCs expressing TCR-A (BMchim.564-Icos.RAG-TCRA), TCR-B (BMchim.564-Icos.RAG-TCRB), or TCR-C (BMchim.564-Icos.RAG-TCRC). 564Igi (564homo) and 564Igi;Icos-/- (564homo.Icos) sera were included as controls.
Project description:We used protein arrays to measure IgG autoantibodies associated with Connective Tissue Diseases (CTDs) from retrogenic chimeras Sera was isolated from irradiated Icos-/-;CD45.1 mice reconstituted with 564Igi;Icos-/- bone marrow mixed with Icos-/-;CD45.1 bone marrow and WT bone marrow (BMchim.564) or retrogenic HSCs expressing TCR-A (BMchim.564-Icos.RAG-TCRA), TCR-B (BMchim.564-Icos.RAG-TCRB), or TCR-C (BMchim.564-Icos.RAG-TCRC). 564Igi (564homo) and 564Igi;Icos-/- (564homo.Icos) sera were included as controls.
Project description:The carboxy-terminal domain (CTD) of the largest subunit of RNA Polymerase II (RNAPII) consists of multiple tandem repeats of the heptapeptide consensus Y1-S2-P3-T4-S5-P6-S7. RNAPII CTD is intrinsically disordered and has been shown to promote liquid-liquid phase-separation (LLPS) of RNAPII in vivo. However, understanding the precise role of the conserved heptad residues in LLPS has been hampered by the lack of direct characterization of the biochemical properties of the CTD. Here, we generated a systematic array of RNAPII CTD variants to unravel the sequence-encoded molecular grammar underlying LLPS of the human CTD.
Project description:Transcription termination in Saccharomyces cerevisiae can be performed by at least two distinct pathways and is directed by the phosphorylation status of the carboxy-terminal domain (CTD) of RNA polymerase II (Pol II). Late termination of mRNAs is performed by the CPF/CF complex and requires CTD-Ser2 phosphorylation. Early termination of shorter cryptic unstable transcripts (CUTs) and small nucleolar RNAs (snoRNAs) is preformed by the Nrd1 complex, and requires CTD-Ser5 phosphorylation. In this study, mutants of the different termination pathways were compared by genome-wide expression analysis. Surprisingly, the expression changes observed upon loss of the CTD-Ser2 kinase Ctk1 are more similar to loss of a subunit of the Ser5P binding Nrd1-complex, than to loss of Ser2P binding factors. Tiling array analysis of ctk1Δ reveals readthrough at several hundred sites, including snoRNAs, as reported previously, but also many cryptic unstable transcripts, stable untranslated transcripts (SUTs) and other transcripts. Surprisingly, neither loss of CTK1 nor a Pol II CTD-Ser2 substitution mutant results in a global defect in termination of mRNAs, indicating that Ser2P is not essential for proper termination of most mRNAs. At snoRNA, Nrd1 location is shifted downstream in ctk1∆, indicating defective release rather than recruitment of Nrd1. Weakening the interaction between Nrd1 and Pol II rescues the readthrough in ctk1∆, likely by facilitating Nrd1 release. The termination defect is kinase activity dependent, but cannot be completely explained by loss of CTD-Ser2 phosphorylation , a major substrate of Ctk1, suggesting the involvement of an additional substrate. Mutant alleles of the elongation factor Spt5 rescue ctk1∆-dependent readthrough, indicating a role for Spt5 in this process, perhaps as a substrate of Ctk1. The results show that Ctk1 is more intimately involved in termination of small non-coding RNAs than was previously assumed and lead to a model in which Ctk1 influences Spt5 activity to achieve this.
Project description:We tested orphan TCR autoreactivity using the peptide MHC-TCR chimeric receptor (MCR) co-culture system. In this system, cognate antigen recognition leads to TCR specific NFAT activation in MCR reporter cells expressing a mouse I-Ab MHC class II extracellular domain covalently linked to candidate peptides and an intracellular TCR signaling domain. We used mixed autoimmune bone marrow chimera spleens and kidneys as sources of cDNA to generate a transcriptome-wide library of natural autoantigen peptides . We cloned this cDNA-derived peptide (CDP) autoantigen library into the MCR retroviral backbone and transduced NFAT reporter cells to make a murine autoantigen MCR reporter library (MCR-Lib). We then used this library to screen orphan TCRs identified by scTCR-seq for autoreactivity.