RESUMO
Shwachman-Diamond Syndrome (SDS) is a multi-system genetic disorder with bone marrow failure. SBDS, the gene associated with SDS, has been postulated to play a role in ribosome biogenesis and RNA processing, but its functions are still unknown. To study whether these pathways are interrupted when Sbds protein is lost, we studied the expression of related genes in patient SBDS-/- cells by an oligonucleotide microarray. We first analysed ribosomal protein (RP) genes, which are normally co-regulated. In SDS, 27 of the 85 RP genes were downregulated. Among the downregulated RP genes, seven are known to be associated with the inhibition of apoptosis. RPS27L, which mediates p53-dependent induction of apoptosis, was the only upregulated RP gene. Interestingly, several genes involved in RP mRNA transcription were downregulated without affecting the expression of genes involved in mRNA degradation, suggesting that the downregulation of the RP gene expression might be at the transcriptional level. Importantly we also found dysregulation of multiple genes involved in rRNA transcription and pre-rRNA processing. We conclude that SDS marrow cells exhibit major dysregulation of RP, RNA processing and RNA transcription genes.
Assuntos
Células da Medula Óssea/metabolismo , Doenças da Medula Óssea/genética , Insuficiência Pancreática Exócrina/genética , Processamento Pós-Transcricional do RNA , Proteínas Ribossômicas/genética , Doenças da Medula Óssea/metabolismo , Estudos de Casos e Controles , Insuficiência Pancreática Exócrina/metabolismo , Perfilação da Expressão Gênica , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , RNA/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Proteínas Ribossômicas/metabolismo , Síndrome , Transcrição GênicaRESUMO
The syndrome of ataxia-pancytopenia is an autosomal dominant disorder characterized by cerebellar ataxia, peripheral neuropathies, pancytopenia and a predilection to myelodysplastic syndrome and acute myeloid leukemia. The genetic basis of this condition is unknown. We describe a child who presented with ataxia and pancytopenia and was found to have a heterozygous mutation, c.845G>A (Arg282His) in TINF2, a gene recently reported to be mutated in a subset of patients with autosomal dominant dyskeratosis congenita. We propose that some cases of ataxia-pancytopenia may be affected by DC.
Assuntos
Ataxia Cerebelar/genética , Pancitopenia/genética , Mutação Puntual , Proteínas de Ligação a Telômeros/genética , Adulto , Substituição de Aminoácidos , Sequência de Bases , DNA/genética , Disceratose Congênita/genética , Feminino , Genes Dominantes , Humanos , Lactente , Masculino , Síndrome , Telômero/genéticaRESUMO
Mapping protein-protein interactions is an invaluable tool for understanding protein function. Here, we report the first large-scale study of protein-protein interactions in human cells using a mass spectrometry-based approach. The study maps protein interactions for 338 bait proteins that were selected based on known or suspected disease and functional associations. Large-scale immunoprecipitation of Flag-tagged versions of these proteins followed by LC-ESI-MS/MS analysis resulted in the identification of 24,540 potential protein interactions. False positives and redundant hits were filtered out using empirical criteria and a calculated interaction confidence score, producing a data set of 6463 interactions between 2235 distinct proteins. This data set was further cross-validated using previously published and predicted human protein interactions. In-depth mining of the data set shows that it represents a valuable source of novel protein-protein interactions with relevance to human diseases. In addition, via our preliminary analysis, we report many novel protein interactions and pathway associations.
Assuntos
Proteínas/metabolismo , Espectrometria de Massas por Ionização por Electrospray/métodos , Humanos , Imunoprecipitação , Ligação ProteicaRESUMO
The recent abundance of genome sequence data has brought an urgent need for systematic proteomics to decipher the encoded protein networks that dictate cellular function. To date, generation of large-scale protein-protein interaction maps has relied on the yeast two-hybrid system, which detects binary interactions through activation of reporter gene expression. With the advent of ultrasensitive mass spectrometric protein identification methods, it is feasible to identify directly protein complexes on a proteome-wide scale. Here we report, using the budding yeast Saccharomyces cerevisiae as a test case, an example of this approach, which we term high-throughput mass spectrometric protein complex identification (HMS-PCI). Beginning with 10% of predicted yeast proteins as baits, we detected 3,617 associated proteins covering 25% of the yeast proteome. Numerous protein complexes were identified, including many new interactions in various signalling pathways and in the DNA damage response. Comparison of the HMS-PCI data set with interactions reported in the literature revealed an average threefold higher success rate in detection of known complexes compared with large-scale two-hybrid studies. Given the high degree of connectivity observed in this study, even partial HMS-PCI coverage of complex proteomes, including that of humans, should allow comprehensive identification of cellular networks.
