Search results for "Ribonucleoprotein"
showing 10 items of 76 documents
The nuclear autoantigen La/SS-B: Mapping and sequencing of the gene and the three retropseudogenes
1997
One target of autoantibodies in sera of patients with systemic lupus erythematosus or primary Sjogren's syndrome is the nuclear autoantigen La/SS-B. Lambda clones and cosmids were isolated, which contained the sequences of the La gene and the three La pseudogenes. They were used for preparation of a physical map. Finally, the La gene and pseudogenes were sequenced. The pseudogenes were characterized as retropseudogenes. Their evolutionary ages were estimated to be approx. 4, 4.5 and 5 million years. Inserts of 4, 16 and 24 nucleotides, which were mostly A-residues, were found in exon 7 of the respective pseudogene. The oldest pseudogene contained the longest insert, the youngest pseudogene …
Characterization of murine monoclonal antibodies against the Ro52 autoantigen
1997
SUMMARY Immunization of BALB/c mice with purified recombinant human Ro52 protein resulted in three anti-Ro52 MoAbs termed 2E7, 4C6 and 4F11. All anti-Ro52 MoAbs specifically reacted with recombinant human Ro52 protein, and also with Ro52 protein in total extracts of all human cell lines analysed, including the epithelial cell line HeLa, the B cell line Raji, the bladder carcinoma cell line RT112, and a fibroblast cell line derived from patients with xeroderma pigmentosum. The anti-Ro52 MoAbs were able to immunoprecipitate the recombinant human Ro52 protein expressed in wheat germ extract, but failed to precipitate hY RNAs from cell extracts. The staining pattern of the MoAbs strongly differ…
Different La/SS-B mRNA isoforms are expressed in salivary gland tissue of patients with primary Sjogren's syndrome
1996
Recently we isolated a La/SS-B mRNA isoform from a cDNA library made from peripheral blood lymphocytes of a patient with primary Sjögren's Syndrome. In the La/SS-B mRNA isoform the exon 1 was replaced. The alternative exon was termed exon 1'. Genomic analysis showed that the exon 1' La mRNA was the result of a promoter-switch in combination with alternative splicing. Due to the unusual structure of the exon 1' La/SS-B mRNA, the function and the behaviour under physiological and pathophysiological conditions in tissue of patients with primary Sjögren's syndrome or Systemic Lupus Erythematosus remained obscure. Therefore assays were established allowing a qualitative and quantitative estimati…
An altered intracellular distribution of the autoantigen La/SS-B when translated from a La mRNA isoform.
1997
Abstract Transcription of the gene encoding for the nuclear autoantigen La resulted in La mRNA isoforms. A promoter switching combined with an alternative splicing pathway replaced exon 1 with exon 1′. Similar to mRNAs encoding for ribosomal proteins, exon 1′ started with a pyrimidine-rich 5′-terminus. Moreover, exon 1′ contained 5′-GC-rich regions and an oligo(U)-tail of 23 uridine residues. Exon 1′ encoded for three open reading frames upstream of the La protein reading frame. In spite of this unusual structure, exon 1′ La mRNAs were translated not only in vitro but also in transiently transfected cells. The translational efficiency of exon 1′ La mRNA was about 14% of exon 1 La mRNA using…
Anti-Inflammatory Action of Heterogeneous Nuclear Ribonucleoprotein A2/B1 in Patients with Autoimmune Endocrine Disorders
2019
Our previous studies documented that human fibroblast-limbal stem cells (f-LSCs) possess immunosuppressive capabilities, playing a role in regulating T-cell activity. This study highlights the molecular activities by which human f-LSCs can attenuate the inflammatory responses of self-reactive peripheral blood mononuclear cells (PBMCs) collected from patients with autoimmune endocrine diseases (AEDs). Anti-CD3 activated PBMCs from twenty healthy donors and fifty-two patients with AEDs were cocultured on f-LSC monolayer. 2D-DIGE proteomic experiments, mass spectrometry sequencing and functional in vitro assays were assessed in cocultured PBMCs. We identified the downmodulation of several huma…
Similar Regulation of Human Inducible Nitric-oxide Synthase Expression by Different Isoforms of the RNA-binding Protein AUF1
2008
The ARE/poly-(U) binding factor 1 (AUF1), a protein family consisting of four isoforms, is believed to mediate mRNA degradation by binding to AU-rich elements (ARE). However, evidence exists that individual AUF1 isoforms may stabilize ARE-containing mRNAs. The 3'-untranslated region of the human inducible nitric-oxide synthase (iNOS) contains five AREs, which promote RNA degradation. We have recently shown that the RNA-binding protein KSRP is critically involved in the decay of the iNOS mRNA. In this study we examined the effects of the individual AUF1 isoforms on iNOS expression. Overexpression of each AUF1 isoform reduces iNOS expression on mRNA and protein levels to the same extent by mo…
Transfection analysis of expression of mRNA isoforms encoding the nuclear autoantigen La/SS-B
1997
Transcription of the gene encoding for the nuclear autoantigen La resulted in La mRNA isoforms. A promoter switching combined with an alternative splicing pathway replaced the exon 1 with the exon 1'. The exon 1' contained GC-rich regions and an oligo(U) tail of 23 uridine residues. Moreover, it encoded for three open reading frames upstream of the La protein reading frame. Despite this unusual structure, when exon 1' La mRNAs were expressed in transfected cells, both exon 1 and 1' La mRNAs were translated to La protein, whereas the upstream open reading frames of the exon 1' were not translated. In addition to full-length exon 1' La mRNAs 5'-shortened exon 1' La mRNAs were detected. The ex…
Identification of nuclear proteins which interact with H1° mRNA.
2012
In developing rat brain the synthesis of H1° histone is mainly regulated at posttranscriptional level and probably depends on RNA-binding proteins (RBPs) (1). We previously identified RBPs apparently specific for this messenger (2) and cloned two novel proteins by screening an expression cDNA library by binding to radiolabeled RNA (3-10). Here we report the use of biotinylated H1° RNA as bait to isolate by chromatography nuclear proteins which interact with H1° mRNA. We identified by mass spectrometry abundant RBPs and molecular chaperones. By western blot we also evidenced, among the RNA-bound proteins, the cold shock domain-containing protein 2 (CSD-C2, also know as PIPPin), a brain-enric…
Activation of oligodendroglial Fyn kinase enhances translation of mRNAs transported in hnRNP A2-dependent RNA granules.
2008
Central nervous system myelination requires the synthesis of large amounts of myelin basic protein (MBP) at the axon–glia contact site. MBP messenger RNA (mRNA) is transported in RNA granules to oligodendroglial processes in a translationally silenced state. This process is regulated by the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 binding to the cis-acting A2 response element (A2RE). Release of this repression of MBP mRNA translation is thus essential for myelination. Mice deficient in the Src family tyrosine kinase Fyn are hypomyelinated and contain reduced levels of MBP. Here, we identify hnRNP A2 as a target of activated Fyn in oligodendrocytes. We show that…
Heterogeneous nuclear ribonucleoprotein (hnRNP) F is a novel component of oligodendroglial RNA transport granules contributing to regulation of myeli…
2011
Myelin basic protein (MBP) is a major component of central nervous system (CNS) myelin. The absence of MBP results in the loss of almost all compact myelin in the CNS. MBP mRNA is sorted into RNA granules that are transported to the periphery of oligodendrocytes in a translationally inactive state. A central mediator of this transport process is the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 that binds to the cis-acting A2-response element in the 3′UTR of MBP mRNA. Recently, we found that activation of the Src family nonreceptor tyrosine kinase Fyn in oligodendrocytes leads to phosphorylation of hnRNP A2 and to increased translation of MBP mRNA. Here, we identify…