RESUMO
The conserved TREX complex, which contains UAP56, Aly, CIP29, and the multi-subunit THO complex, functions in mRNA export. Recently, several putative new components of the human TREX complex were identified by mass spectrometry. Here, we investigated the function of two of these, PDIP3 and ZC11A. Our data indicate that both of these proteins are components of a common TREX complex and function in mRNA export. Recently, we found that both CIP29 and Aly associate with the DEAD box helicase UAP56 and with the TREX complex in an ATP-dependent manner. We now show that this is also the case for PDIP3 and ZC11A. Thus, together with previous work, our data indicate that the TREX complex participates in multiple ATP-dependent interactions.
Assuntos
Trifosfato de Adenosina/metabolismo , Proteínas de Transporte/metabolismo , Proteínas Nucleares/metabolismo , Transporte de RNA , Proteínas de Ligação a RNA/metabolismo , Sequência de Aminoácidos , Proteínas de Transporte/química , Células HeLa , Humanos , Dados de Sequência Molecular , Proteínas Nucleares/química , Ligação Proteica , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/química , Dedos de ZincoRESUMO
BACKGROUND: The somatic genetic basis of chronic lymphocytic leukemia, a common and clinically heterogeneous leukemia occurring in adults, remains poorly understood. METHODS: We obtained DNA samples from leukemia cells in 91 patients with chronic lymphocytic leukemia and performed massively parallel sequencing of 88 whole exomes and whole genomes, together with sequencing of matched germline DNA, to characterize the spectrum of somatic mutations in this disease. RESULTS: Nine genes that are mutated at significant frequencies were identified, including four with established roles in chronic lymphocytic leukemia (TP53 in 15% of patients, ATM in 9%, MYD88 in 10%, and NOTCH1 in 4%) and five with unestablished roles (SF3B1, ZMYM3, MAPK1, FBXW7, and DDX3X). SF3B1, which functions at the catalytic core of the spliceosome, was the second most frequently mutated gene (with mutations occurring in 15% of patients). SF3B1 mutations occurred primarily in tumors with deletions in chromosome 11q, which are associated with a poor prognosis in patients with chronic lymphocytic leukemia. We further discovered that tumor samples with mutations in SF3B1 had alterations in pre-messenger RNA (mRNA) splicing. CONCLUSIONS: Our study defines the landscape of somatic mutations in chronic lymphocytic leukemia and highlights pre-mRNA splicing as a critical cellular process contributing to chronic lymphocytic leukemia.
Assuntos
DNA de Neoplasias/análise , Leucemia Linfocítica Crônica de Células B/genética , Mutação , Spliceossomos/genética , Adulto , Deleção Cromossômica , Cromossomos Humanos Par 11/genética , Exoma/genética , Biblioteca Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Mutação de Sentido Incorreto , Splicing de RNARESUMO
Duplex formation between the branch point-binding region (BBR) of U2 snRNA and the branch point sequence (BPS) in the intron is essential for splicing. Both the BBR and BPS interact with the U2 small nuclear ribonucleoprotein (snRNP)-associated SF3b complex, which is the target of the anti-tumor drug E7107. We show that E7107 blocks spliceosome assembly by preventing tight binding of U2 snRNP to pre-mRNA. E7107 has no apparent effect on U2 snRNP integrity. Instead, E7107 abolishes an ATP-dependent conformational change in U2 snRNP that exposes the BBR. We conclude that SF3b is required for this remodeling, which exposes the BBR for tight U2 snRNP binding to pre-mRNA.