Project description:Here we present the study on ChIP-chip mapping of the genomic binding sites for Sty1, Atf1, and the Atf1's binding partner Pcr1; the genome-wide transcriptional profiling of the atf1 and pcr1 strains in response to H2O2; and the phenotypic assessment of ~90 Atf1/Pcr1-bound or unbound genes for growth fitness under H2O2 conditions. ChIP-chip analysis shows that Atf1 and Pcr1 binding sites are overlapped in the genome and constitutively present before H2O2 stress. On the other hand, Sty1 recruitment primarily occurs at the Atf1/Pcr1 binding sites and is induced by H2O2. We found that Atf1/Pcr1 is clearly responsible for the high-level transcriptional response to H2O2. Furthermore, phenotypic assessment indicates that among the H2O2-induced genes, Atf1/Pcr1-bound genes exhibit a higher likelihood of functional requirement for growth fitness under the stress condition than the Atf1/Pcr1-unbound genes do. Notably, we found that the Atf1/Pcr1-bound genes regardless of their responsiveness to H2O2 show a high probability of requirement for growth fitness. . Expression level of genes in triplicates at 0min (without stress) is compared with that at 10, 30, 60, and 120min after stress treatment. ChIP-chip analyses is done for Atf1-HA, pcr1-HA, sty1-HA, Sty1-HA allele in the atf1D or pcr1D background without and with H2O2 (0.5mM for 30min).
Project description:To better understand the problems associated with cloning, gene expression profiling of AI- and SCNT-derived bovine (day 25 of pregnancy) fetuses was performed. The embryonic disc and the extraembryonic tissues for each fetus were analyzed separately using a bovine oligoarray. Clustering of all the expression profiles showed clustering by tissue, but no separation of AI vs. SCNT samples was observed. Statistical analysis using a mixed model revealed 188 differentially expressed genes between the extraembryonic tissues and 10 differentially expressed genes between the embryonic discs of AI- and SCNT-derived fetuses. Between the tissue types >9,000 genes showed differential expression, of which 2,127 that showed >=2-fold difference in expression. The data generated in the current experiment clearly shows that the main problem with SCNT pregnancies is related to abnormal gene expression in the extraembryonic tissues. Keywords: nuclear transfer Ref design with dye swap
Project description:The G2 DNA damage checkpoint inhibits Cdc2 and mitotic entry through the dual regulation of Wee1 and Cdc25 by the Chk1 effector kinase. Up-regulation of Chk1 by mutation or overexpression bypasses the requirement for up-stream regulators or DNA damage to promote a G2 cell cycle arrest. We screened in fission yeast for mutations that rendered cells resistant to overexpressed Chk1. We identified a mutation in tra1, which encodes one of two homologs of TRRAP, an ATM/R-related pseudokinase that scaffolds several histone acetyltransferase (HAT) complexes. Inhibition of histone deacetylases reverts the resistance to overexpressed Chk1, suggesting this phenotype is due to a HAT activity, though expression of checkpoint and cell cycle genes is not greatly affected. Cells with mutant or deleted tra1 activate Chk1 normally and are checkpoint proficient. However, these cells are semi-wee even when overexpressing Chk1, and accumulate inactive Wee1 protein. The Cdr (changed division response) kinases Cdr1 and Cdr2 are negative regulators of Wee1, and while best characterized in the cellular response to limited nutrition, we show that they are required for the Tra1-dependent alterations to Wee1 function. This identifies Tra1 as another component controlling the timing of entry into mitosis via Cdc2 activation. Two and three independent microaaray experiments were done for wild type and the mutant (tra1-1) respectively.
Project description:Cows were selected from two groups of 12 cows enrolled in a large experiment to assess the effects of ad libitum or restricted intake of moderate-energy diets during the entire dry period on pre-partum metabolism and post-partum metabolism and performance. A corn silage-based diet (26% of diet dry matter) providing 1.59 Mcal/kg during the far-off dry period (first 5 wk of an 8-wk dry period) or providing 1.61 Mcal/kg during the close-up dry period (last 3 wk of the dry period) was fed for ad libitum or restricted intake. Four multiparous Holstein cows were randomly selected from the ad libitum and restricted intake groups. A 7,872-element cDNA microarray spotted in duplicate on amino silane-coated glass slides (Everts et al. 2005, Vet. Immunol. Immunopathol. 105:235-245) was used for transcript profiling. Annotation was based on similarity searches (January, 2005) using sequential BLASTN and TBLASTX against human and mouse UniGene databases and the human genome. The 7,872-element array represents more than 6,300 unique genes. Gene Ontology (GO) terms were parsed from LocusLink to functionally annotate cDNA sequences. RNA (20 ug) from liver tissue and a reference standard derived from a mixture of tissues not including liver were used to make aminoallyl-labeled cDNA followed by incorporation of Cy3-ester and Cy5-ester (Amersham, Piscataway, NJ). Each experimental sample was co-hybridized with the reference standard, which allowed the treatment of fluorescence ratios as measurements of relative expression across all samples and time points. Probes were hybridized to the array for 2 days at 42 C. All samples were hybridized to duplicate slides for a total of 4 spots per cDNA element. A total of 106 microarrays were run to complete the experiment. Slides were scanned for both dye channels with a Scanarray 4000 (GSI-Lumonics, Billerica, MA) dual-laser confocal scanner and images were processed using GenePix 4.0 (Axon Instruments, Inc., CA).
Project description:In vitro production (IVP) has been shown to affect embryonic gene expression and often result in large offspring syndrome (LOS) in cattle and sheep. To dissect the effects of in vitro maturation, fertilization and culture, we compared the expression profiles of single bovine blastocysts generated by: 1) in vitro maturation, fertilization and culture (IVF); 2) in vivo maturation, fertilization and in vitro culture (IVD); and 3) in vivo maturation, fertilization and development (AI). To conduct expression profiling, total RNA was isolated from individual embryos, linearly amplified and hybridized to a custom bovine cDNA microarray containing approximately 6,300 unique genes. There were 306, 367 and 200 genes differentially expressed between the AI and IVD, IVF and IVD and AI and IVF comparisons, respectively. Interestingly, 44 differentially expressed genes were identified between the AI embryos and both the IVF and IVD embryos, making these potential candidates for LOS. There were 60 genes differentially expressed between the IVF embryos and the AI and IVD embryos. The Gene Ontology category M-bM-^@M-^\RNA processingM-bM-^@M-^] was over-represented among the genes that were down-regulated in the IVF embryos, indicating an effect of in vitro oocyte maturation/fertilization on embryonic gene expression. A culture effect on the expression of genes involved in translation was also observed by the comparison of AI to IVD embryos. Reference design with dye swap. 43 individual embryos were analyzed.
Project description:DNA replication is initiated at multiple sites or origins enriched with AT-rich sequences at various times during the S-phase. While current studies of genome-wide DNA replication profiles have focused on the timing of replication and the location of origins, the efficiency of replication/firing at various origins remains unclear. In this study, we show different efficiencies of DNA replication at various loci by using ORF-specific DNA microarrays. DNA copy-number increases as a function of time at individual loci are approximated to near-sigmoidal models for estimation of replication initiation and completion timings in HU-challenged cells. Duplicating times (from initiation to completion) vary from loci to loci, partly contributing to various firing efficiencies at origins. DNA replication timing profiles are strikingly similar to the reported patterns of enriched ssDNA, suggesting that majority stalled forks are restored for resumption of DNA replication. Although the DNA replication timing profiles are disrupted in HU-challenged cds1? cells, ~85% of potential origins overlapped with those found in wild type cells, significantly, most of which represents inefficiently fired origins in wild type cells. Together, our result indicates that replication checkpoint plays a role in monitoring efficient origins and thus maintaining global DNA replication patterns in HU-challenged cells. Keywords: WT or Cds1 HU synchronized cells released in HU free media and harvested at different time points vs WT or Cds1 synchronized with HU for 3 hrs. We analyzed 32 arrays for WT and 38 arrays for Cds1 cells which were synchronized with HU and released in HU free media and harvested at different time points. At least two biological repeats were done for each time points.
Project description:Expression profiles indicate that C-terminal of rep2 is essential for its transactivation activity. Keywords: rep2 mutants cells treated with 8 mM HU for different time points vs wildtype untreated cells We analyzed 40 arrays for rep2 mutants cells treated with 8 mM HU to wild type cells.
Project description:Expression profiles of polg mutant cells reveal that many genes encoding proteins involved in cell wall biogenesis and stress response are induced, suggesting that polg mutant cells attempt to maintain growth potential and undergo extensive oxidative metabolism. Conversely, many genes encoding proteins involved in ribosome biogenesis and respiration are repressed, indicating that cells depleted of mtDNA are adapted to grow slowly in absence of mitochondrial function. We analyzed 5 arrays of polyg mutant cells vs wild type cells.
Project description:Liver from five Holstein cows fed to current National Research Council (2001) recommendations during the dry period and early lactation was biopsied at -65, -30, -14, 1, 14, 28, and 49 days relative to parturition. cDNA from liver and a reference standard (made from cattle tissues not including liver or mammary) were labeled with Cy3 or Cy5 fluorescent dye and co-hybridized to our 7,872 bovine cDNA microarray using a dye-swap design. More than 5,000 sequences present on the array were expressed in liver. Normalized log-transformed ratios (liver/reference) were analyzed using a MIXED model in SAS. Keywords: cow, liver, lactation, microarray, periparturient period
Project description:The Notch signaling is an evolutionarily conserved signal transduction cascade that plays essential roles in a variety of developmental processes. In this study, we examined the mib mutants for defects in pancreas development using in situ hybridization and GFP expression analysis of pancreas-specific GFP lines, and carried out the global gene expression profile analysis of three different mib mutantalleles. Global expression profile analysis showed that there is a significant difference in gene expression profile of wild type and three mib mutant alleles. There are 91 differentially expressed genes that are common to all three mib alleles. Through detailed analysis of microarray data we have identified several previously characterized genes and some putative Notch-responsive genes involved in pancreas development, and validated theirexpression profile using real-time PCR and in situ hybridization. We propose that this study provides a useful resource of global gene expressionprofile in mib mutants, which will be helpful in identifying the function of novel genes involved in Notch signaling and Notch-responsive genesinvolved in a variety of developmental processes. Keywords: comparison of global gene expression in mib mutant and wild type embryos All samples were analysed on Zebrafish microarray chips generated at the Genome Institute of Singapore