RESUMO
NSD3/WHSC1L1 histone methyltransferase gene aberrations are observed in leukemia and in breast and lung carcinomas, suggesting that NSD3 is implicated in carcinogenesis. In this study we examined in human breast cancer cells the NSD3L isoform which contains the catalytic histone methyltransferase SET-domain. siRNA directed depletion of NSD3L followed by genome-wide microarray analysis identified NSD3L regulated genes which could be functionally linked to cellular signaling pathways such as cell growth, cell cycle, cell motility, transcription, and apoptosis. Notably up-regulated genes are the cell cycle regulators E2F2 and Arl2. In accordance with a function of NSD3L in cell cycle regulation NSD3L depletion resulted in an increase in the number of cells in the S and G2/M cell cycle phases. Moreover, NSD3L depletion increased the invasiveness of MDA-MB-231 breast cancer cells indicating that NSD3L normally restrain cellular metastatic potential. Together the presented data indicates that NSD3L is a candidate tumor suppressor.
Assuntos
Neoplasias da Mama/patologia , Ciclo Celular/genética , Regulação Neoplásica da Expressão Gênica , Histona-Lisina N-Metiltransferase/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Neoplasias da Mama/enzimologia , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Feminino , Estudo de Associação Genômica Ampla , Histona-Lisina N-Metiltransferase/genética , Humanos , Invasividade Neoplásica , Proteínas Nucleares/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Interferente Pequeno/genética , Proteínas Supressoras de Tumor/genéticaRESUMO
The intermediate filament protein vimentin is involved in a variety of cellular functions both during the normal developmental processes and in human malignancies. We here describe the identification of an alternative vimentin transcript initiating upstream for the canonical vimentin gene promoter and spliced using the vimentin promoter sequence as an intron. Expression analysis showed that the alternative vimentin promoter had the same expression profile as the canonical vimentin gene promoter. The presented data suggest that alternative promoter usage and alternative splicing could be regulatory mechanisms participating in vimentin gene regulation.
Assuntos
Regiões Promotoras Genéticas , Vimentina/genética , Processamento Alternativo/genética , Sequência de Bases , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Humanos , Dados de Sequência Molecular , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Vimentina/metabolismoRESUMO
Type III interferon (IFN) is a novel member of the interferon family. Type III IFN utilizes a receptor complex different from that of type I IFN, but both types of IFN induce STAT1, STAT2, and STAT3 activation. Here we describe a detailed comparison of signal transduction initiated by type I and type III IFN. Gene expression array analysis showed that IFN types I and III induced a similar subset of genes. In particular, no genes were induced uniquely by type III IFN. Next, we used chromatin immunoprecipitation (ChIP) analysis to investigate the promoter activation by types I and III IFN. The ChIP assays demonstrated that stimulation of cells with both type I and type III IFN resulted in the recruitment of ISGF3 transcription factor components to the promoter region of responsive genes and in an increase of polymerase II loading and histone acetylation. Whereas IFN type I signaling was observed for a broad spectrum of cell lines, type III IFN signaling was more restricted. The lack of IFN type III signaling was correlated with a low expression of the IL28Ra component of the IFN type III receptor, and IL28Ra overexpression was sufficient to restore IFN type III signaling. We also tested the activation of mitogen-activated protein (MAP) kinases by type III IFN and found that type III IFN relies strongly upon both p38 and JNK MAP kinases for gene induction.