Human toxicogenomic studies to date have been of limited size, have mainly addressed exposures at the upper end of typical ranges of human exposure, and have often lacked precise, individual estimates of exposure. Previously, we identified genes associated with exposure to high (>10 ppm) levels of the leukemogen, benzene, through transcriptomic analyses of blood cells from small numbers of occupationally exposed workers. Here, we have expanded the study to 125 workers exposed to a wide range of benzene levels, including <1 ppm. Study design, and analysis with a mixed effects model, removed sources of biological and experimental variability and revealed highly significant widespread perturbation of gene expression at all exposure levels. Benzene is an established cause of acute myeloid leukemia (AML), and may cause one or more lymphoid malignancies in humans. Interestingly, acute myeloid leukemia was among the most significant pathways impacted by benzene exposure in the present study. Further, at most exposure levels, immune response pathways including T cell receptor signaling, B cell receptor signaling, and Toll like receptor signaling were impacted, providing support for the biological plausibility of an association between lymphoma and benzene exposure. We also identified a 16-gene expression signature modified by all levels of benzene exposure, comprising genes with roles in immune response, inflammatory response, cell adhesion, cell-matrix adhesion, and blood coagulation. Overall, these findings support, and expand upon, our current understanding of the mechanisms by which benzene may induce hematotoxicity, leukemia and lymphoma. Furthermore, this study shows that with good study design and analysis, transcriptome profiling of the blood of chemically-exposed humans can identify relevant biomarkers across a range of exposures and inform about potential associations with disease risks.
Global gene expression profiling of a population exposed to a range of benzene levels.
Sex, Age, Subject
View SamplesIn theses experimetns we have analized the differential gene expression profile in human trabecular meshwork cells phagocytically challenged to E. coli and pigment under physiological and oxidative stress conditions using affymetrix microarrays
Up-regulated expression of extracellular matrix remodeling genes in phagocytically challenged trabecular meshwork cells.
Specimen part
View SamplesThe transmission of information about the photic environment to the circadian clock involves a complex array of neurotransmitters, receptors, and second messenger systems. Using laser capture microscopy and microarray analysis, a population of genes rapidly induced by light in the suprachiasmatic nucleus is identified.
Identification of novel light-induced genes in the suprachiasmatic nucleus.
No sample metadata fields
View SamplesFull title: Altered levels of MOF (member of MYST family histone acetyl transferase) and decreased levels of H4K16ac correlate with a defective DNA damage response (DDR).
MOF and histone H4 acetylation at lysine 16 are critical for DNA damage response and double-strand break repair.
Specimen part, Cell line
View SamplesChromosomal rearrangements involving the mixed-lineage leukemia (MLL) gene occur in primary and treatment-related leukemias, and confer a poor prognosis. Studies based primarily on mouse models have substantially advanced our understanding of MLL leukemia pathogenesis, but often employ supra-physiologic oncogene expression with uncertain implications for human leukemia. Genome editing using site-specific nucleases provides a powerful new technology for gene modification to potentially model human disease, however this approach has not been used to recreate acute leukemia in human cells of origin comparable to disease observed in patients. We applied TALEN-mediated genome editing to generate endogenous MLL-AF9 and MLL-ENL oncogenes through insertional mutagenesis in primary human hematopoietic stem and progenitor cells (HSPCs) derived from human umbilical cord blood. Engineered HSPCs displayed altered in vitro growth potentials and induced acute leukemias following transplantation in immuno-compromised mice at a mean latency of 14.5 weeks. The leukemias displayed phenotypic and morphologic similarities with patient leukemia blasts including a subset with mixed phenotype, a distinctive feature seen in clinical disease. The leukemic blasts expressed an MLL-associated transcriptional program with elevated levels of crucial MLL target genes, displayed heightened sensitivity to DOT1L inhibition, and demonstrated increased oncogenic potential ex vivo and in secondary transplant assays. Thus, genome editing to create endogenous MLL oncogenes in primary human HSPCs faithfully models acute MLL-rearranged leukemia and provides an experimental platform for prospective studies of leukemia initiation and stem cell biology in a genetic subtype of poor prognosis leukemia.
MLL leukemia induction by genome editing of human CD34+ hematopoietic cells.
Specimen part
View SamplesDetermination of gene expression changes in hindlimb muscle (gastrocnemius/soleus) of mdx (dystrophin-deficient) mice at postnatal ages 7, 14, 23, 28, 56, and 112.
Dissection of temporal gene expression signatures of affected and spared muscle groups in dystrophin-deficient (mdx) mice.
No sample metadata fields
View SamplesAn important component of time course microarray studies is the identification of genes that demonstrate significant time-dependent variation in their expression levels. Until recently available methods for performing such significance tests required replicates of individual time points. This paper describes a replicate-free method that was developed as part of a study of the estrous cycle in the rat mammary gland in which no replicate data was collected.
Identifying significant temporal variation in time course microarray data without replicates.
No sample metadata fields
View SamplesDetermination of gene expression changes in extraocular muscle of mdx (dystrophin-deficient) mice at postnatal ages 14, 28, 56, and 112 days. 3 independent replicates/age/strain.
Dissection of temporal gene expression signatures of affected and spared muscle groups in dystrophin-deficient (mdx) mice.
No sample metadata fields
View SamplesRhesus monkey extraocular muscle. Data set includes: (a) whole medial and lateral rectus muscle and (b) global and orbital muscle layers separately microdissected using a Leica LSM. All samples were expression profiled here using the Affymetrix human U133 A&B arrays. Data form part of publication: Investigative Ophthalmology and Visual Science 45, 2004.
Genome-wide transcriptional profiles are consistent with functional specialization of the extraocular muscle layers.
No sample metadata fields
View SamplesPUF proteins have become a leading scaffold for designing RNA-binding proteins to contact and control RNAs at will. We analyze the effects of that reengineering across the transcriptome in vivo for the first time. We show, by HITS-CLIP and PAR-CLIP, that S. cerevisiae Puf2p, a non-canonical PUF protein, binds more than 1000 mRNA targets. Puf2p binds multiple UAAU elements, unlike canonical PUF proteins. We also perform CLIP-seq on truncations of Puf2p, showing that its prion domain is dispensable for WT binding. We design a modified Puf2p to bind UAAG rather than UAAU, which allows us to align the protein with the binding site. In vivo, the redesigned protein binds UAAG sites. Its altered specificity redistributes the protein away from 3'UTRs, such that the protein tracks with its sites and binds throughout the mRNA. We use RNA-seq to determine that R1 SNE Puf2p represses a novel RNA network. Overall design: CLIP-seq was performed in BY4742 S. cerevisiae grown in log phase, and using 2 replicates of TAP-tagged proteins. RNA-seq was performed to determine the regulatory effect of WT or mutant Puf2p, using 4 replicates of the control (no Puf2p), 3 of WT Puf2p and 4 of R1 SNE Puf2p.
Target selection by natural and redesigned PUF proteins.
Cell line, Subject
View Samples