5 uM AKTi or the combination for 48 hours Apoptosis was quantifi

5 uM AKTi or the combination for 48 hours. Apoptosis was quantified by anti body mediated capture and detection of cytoplasmic mononucleosome and find more information oligonucleosome associated histone DNA comple es according to the manufacturers instructions. Results were e pressed as the average ab sorbance value of triplicates. Statistical analysis IC50 values were calculated on the basis of the growth inhibition curves and define the concentration of drugs that resulted in 50% growth inhibition. Synergistic, additive or antagonistic effects of the drug combinations were determined by the use of the combination inde method of Chou and Talalay using the Calcusyn software. Any CI values less than 1 indicates synergism, CI 1 additive effect and CI 1 antagonism. Error bars represent the standard error of the mean.

A two tailed unpaired t test was used when applicable. P values 0. 05 were considered to be statistically significant. Background Lung cancer remains the leading cause of cancer related mortality in the United States, and 30% to 40% of newly diagnosed patients with non small cell lung cancer present with regionally advanced and unre sectable stage III disease. Despite recent advances in understanding the molecular biology of lung cancer and the introduction of multiple new chemotherapeutic agents for its treatment, the poor outcomes related to lung cancer have not changed substantially. This justifies the continuing search for agents with therapeutic potential against NSCLC.

Pero isome proliferator activated receptors are ligand inducible nuclear transcription factors that heterodimerize with retinoid receptors and bind to PPAR response elements located in the promoter region of PPAR target genes. The role of PPAR��, one PPAR isotype, has been e tensively studied thanks to the availability of synthetic PPAR�� agonists including antidiabetic drugs, such as rosiglitazone, ciglita zone, and pioglitazone. These drugs are also effective in regulating cell activation, differentiation, proliferation, and apoptosis through both PPAR�� dependent and independ ent signaling. However, the detailed mechanisms re sponsible for these effects remain incompletely elucidated. Stress activated protein kinase c Jun N terminal kinase is a mitogen activated protein kinase family member that is activated by diverse stimuli and plays a critical role in regulating cell fate, being implicated in a multitude of diseases ranging from cancer to neurological, immunological and inflammatory conditions.

JNK signal ing is required for normal mammary gland development and has a suppressive role in mammary tumorigenesis. AMP activated protein kinase, a heterotrimeric protein comple with serine threonine kinase activity, has been involved in the regulation of a number of physio logical processes including B o idation of fatty acids, lipo genesis, protein and AV-951 cholesterol synthesis, as well as cell cycle inhibition and apoptosis.

Microarray ana lysis was performed at the Center for Medical Geno

Microarray ana lysis was performed at the Center for Medical Genomics at the Indiana University selleck School of Medicine. Labeling and hybridization to Affymetrix Mouse Genome 430A GeneChips were carried out following the manufacturers suggested procedure. Fragmented biotinylated RNA from each embryo was separately hybridized to its own GeneChip for 17 hours at 42 C. The microarray analysis revealed striking differ ences among the 4 alcohol treated samples, which segre gated as two separate pairs rather than one set of four, subsequently, it was noted that one pair of embryos had an open neural tube and the other pair had the neural tube closed. All 4 control embryos had closed neural tubes. Experiment 2 was designed to follow up these initial results and provide an independent test of the gene expres sion correlations with the two neural tube phenotypes.

Total RNA was isolated from individual embryos. raction and microarray analysis was as described above, except that Affymetrix Mouse Genome 430 2. 0 GeneChips were used. The Mouse Genome 430A chip contains over 22,600 probe sets representing transcripts and variants from over 14,000 well characterized mouse genes. The newer Mouse Genome 430 2. 0 Array contains all of the probe sets present on the earlier 430A chip plus additional probe sets for a total of approximately 45,000 probe sets that analyze the expression of over 39,000 transcripts and variants from over 34,000 well characterized mouse genes. The differences in feature size and probe set con tent make direct comparisons inappropriate, due to scanning and scaling issues, but because the probe sets on the 430A are present on the 430 2.

0 array, those can be compared at the level of gene lists. The data from independent arrays for each of the treatments were extracted using the Affymetrix Microarray Suite 5. 0 algorithm. Data for both experiments have been deposited in GEO NCBI and have been assigned series accession number GSE9545 and sample numbers GSM241642 through GSM241660. To minimize false positive results, only genes detected on at least half of all individual arrays in at least one experimental condition were retained for further analysis. This avoids data that primarily represent noise. To detect differentially expressed genes, control samples were compared to ALC NTC samples, or ALC NTO samples, or their combination, using a Welchs t test on the log transformed signals.

To see genes that were similarly affected in both experiments, we inter sected the gene lists. To avoid missing genes that met a stringent significance threshold in one experiment but were just beyond that threshold in the second, we chose Brefeldin_A p 0. 05 as the threshold for each experiment. Given that the two experiments were independent, the prob ability that a gene overlaps by chance and differs in the same up down direction in both experiments is 2 0. 00125.

1 in a two tailed Students t test, of which 61 mRNAs differed wit

1 in a two tailed Students t test, of which 61 mRNAs differed with a P value of 0. 05. A subset of these 94 mRNAs are listed in Figure 5A, sorted on the selleck kinase inhibitor mean TE4G TEWT values. Note that most of these mRNAs exhibit relatively high TE values in WT cells but display TEs in the mutant closer to unity. Thus, these genes all exhibit higher than average translational efficiencies in WT cells that are reduced in the mutant to values closer to the genome average TE value. We similarly identified 99 mRNAs exhibiting a higher translational efficiency in the mutant versus WT, with mean TE4G TEWT ratios 1. 4 and for which the differ ence between the mean TE4G and TEWT values was sig nificant at P 0. 1, of which 46 differed with a P value of 0. 05.

As illustrated in Figure 5B, the majority of such mRNAs exhibit lower than average translational efficiencies in WT cells with TEWT values 0. 5, but efficiencies in the mutant that are closer to the genome average TE value. Thus, their relatively low TE values in WT cells are increased on depletion of eIF4G in the mutant. These comparisons support the conclusion that elimi nating eIF4G narrows the range of translational efficien cies at both ends of the spectrum. In an effort to validate the microarray measurements of TE values, we conducted real time qRT PCR analysis of particular mRNAs in the polysomal and total RNA preparations used to produce the Cy3 cDNAs for prob ing microarrays. We analyzed a set of 28 genes, most belonging to the two groups of genes just described with mean TE4G values that are higher or lower than the cognate mean TEWT values by a factor of 1.

4 or more. As shown in Figure S1, the mRNAs identified by microarray analysis with mean TE4G TEWT ratios 1. 4 displayed corresponding TE4G TEWT ratios measured by qRT PCR that were signifi cantly greater than those for mRNAs with mean TE4G TEWT values of 0. 71 in the microarray analysis. Thus, it appears that the microarray analysis reliably identified two groups of genes that are affected oppositely by depletion of eIF4G. Characteristics of genes exhibiting altered translational efficiencies on depletion of eIF4G We wished next to determine whether the genes that displayed the largest differences in translational efficien cies between Dacomitinib mutant and WT cells tend to be involved in common biological processes. To this end, we con ducted a gene ontology analysis using the MIPS Funcat system, which determines whether genes of interest are significantly enriched in particular cellular functions. Analysis of the 99 genes with TE4G TEWT 1. 4, which are translated relatively better on eIF4G depletion, revealed that they were enriched for genes with specific cellular functions.

This is particularly true

This is particularly true selleck chem ARQ197 for innate immunity in cases including acute melioidosis where excessive acti vation of inflammatory genes is commonly associated with septic shock. We did not see up regulation in the levels of anti inflammatory signals and TLR negative regulators at 24 hpi, suggesting that the failure to suppress inflamma tion at this early time point contributes to the excessive inflammation and acute nature of this infection. Neverthe less, at 42 hpi, a significant decrease in expression of these potent inflammatory genes was observed and may actually benefit the intracellular pathogen. However, the underlying factors that contribute to the decrease in expression of these inflammatory genes remain unclear as the production of anti inflammatory cytokines was relatively insufficient to counter the high pro inflammatory responses at 24 hpi.

Acute forms of melioidosis that lead to sepsis, multi ple organ failure and death are thought to result from an uncontrolled inflammatory reaction that ultimately leads to excessive inflammation and eventually tissue injury in the B. pseudomallei infected host. Activation of proteasomal degradation following tissue injury suggests the production of immunological waste products such as apoptotic cells and immune complexes in the B. pseu domallei infected host. This could be attributed to a failure in activating the complement system in time, leading to the accumulation of waste and uncontrolled spread of the pathogen. The low levels of the potent anaphyatoxin C5a observed in our study most likely inhibit the downstream terminal complement pathway.

As a result, deficient rapid clearance of apop totic cells resulting in extracellular disintegration of the cell and release of intracellular components triggers inflammatory cytokine production and contributes to breaking tolerance by facilitating an immune response to intracellular constituents. This is the first evi dence of failure of the downstream complement path way in acute melioidosis. The B. pseudomallei infected host also over express many cell death related genes which suggests that the host initiates various cell death defence responses and disrupts cell regulation to limit a favourable intracellular niche for the pathogens. Elevation of caspase 2, 3, 7 and 8, as well as the BCL 2 family protein BID and TNF receptor superfamily suggests that the host triggers apoptosis signalling via the death receptor mediated pathway.

In addition, we saw an up regulation of inflammasome related genes not pre viously reported in the B. pseudomallei infected host. B. pseudomallei virulence factors such as type three GSK-3 secre tion factors, flagellin and channel forming toxins like hemolysin could trigger inflammasome dependent caspase 1 activation. B. pseudomallei is known to interfere with iNOS expression in RAW264. 7 macrophages and abrogate nitric oxide production during the early stages of infection.

In parallel, we observed that the reverse transport of cholestero

In parallel, we observed that the reverse transport of cholesterol selleck chemicals llc not used by tissues via HDL to the liver was also stimulated in fish fed VD. Indeed, APOA1, which participates in the transport of cholesterol to the liver by promoting cholesterol efflux from tissues and by acting as a cofactor for the lecithin cholesterol acyltransferase, exhibited higher tran script levels in fish fed VD. Altogether these results reveal that another major response in the liver of Eur opean sea bass fed a vegetable diet is the stimulation of cholesterol synthesis and transport, irrespective of the half sibfamily considered. Carbohydrate metabolism LC PUFA and cholesterol biosynthesis require reducing power in the form of NADPH.

It is well documented in vertebrates, including fish, that NADPH required for malonyl CoA synthesis is mainly supplied by the dehy drogenases of the pentose phosphate shunt. Interestingly, our transcriptomic data indicate that the use of the VD induced a significant increase in the level of glucose 6 phosphate dehydrogenase. G6PD catalyses NADP linked oxidation of D glucose 6 phosphate and has been shown to be a major contributor of NADPH production for lipogenesis in Atlantic salmon and European sea bass. Moreover, our data indicate an increase in the expression of hexose 6 phosphate dehydrogenase and phosphogluconate dehydrogenase, enzymes of the pentose phosphate pathway that gener ate NADPH, in fish fed VD. Once synthesized, the resulting pentose sugar intermediate generated by the pentose phosphate pathway can be reconverted to intermediates of the glycolysis gluconeo genesis pathway such as glyceraldehyde 3P or fructose 6P.

In the liver of fish, it is known that glycolysis pro vides essential precursors for biosynthesis rather than pyruvate for oxidation. Thus, the stimulation of fructose 1, 6 bisphosphatase 1 and aldolase expression that we observe in fish fed VD could provide high levels of fructose 6 phosphate from glyceraldehyde 3P, then glucose 6P that serves as substrate for repeated passage in the pentose phosphate shunt. Protein amino acid metabolism and ATP synthesis Our data revealed over expression of genes involved in proteolysis and, more particularly, in proteasome activity and ubiquitin activity in fish fed VD, which is in total agreement with proteomic data obtained in rainbow trout, indicating a stimulation of proteolysis in fish fed vegetable diets. In our study, the stimulation of proteolysis in the fish fed the vegeta ble diet was associated with the induction of 18 genes involved in amino acid metabolism and, more impor tantly, 4 genes involved in glutamine Batimastat metabolism. In addition, gmps, aadat, got1 and tat genes, which are implicated in transamination, were also stimulated in fish fed VD.

Rat recombinant globular adiponectin was purchased from Biovision

Rat recombinant globular adiponectin was purchased from Biovision. Antibodies for the phosphorylated Akt at Ser473, total Akt, cleaved caspase 3, poly poly merase, inhibitor of PI3K LY29002, inhibitor of p ERK1/2 U0126, HRP conjugated anti rabbit or anti mouse secondary selleck chemical Dasatinib antibodies were obtained from Cell Signaling Technology. Antibodies for the phosphorylated at Thr202/Tyr204 extracellular regulated kinase, total ERK1/2, B actin, and Enhanced chemiluminescence reagent were purchased from Millipore. Palmitate and Bovine Serum Albumin were obtained from Sigma Aldrich. The stock solutions 5 mM PA/10% BSA that can be stored at ?20 C was prepared reference from. The 5 mM PA/10% BSA stock solutions are heated for 15 min at 55 C, and then cooled to room temperature before use.

Cell culture H9c2 cells obtained from Chinese Collection of Cell Cultures, were grown in Dul beccos Modified Eagles Medium supplemen ted with 10% fetal bovine serum and 1% penicillin streptomycin in a humidified atmosphere of 95% air 5% CO2 at 37 C. In addition, the various treatments for cells were carried out only when cells reach about 80% of confluence in appropriate culture dish. Nuclear staining with Hoechst 33342 Cell were plated in 6 well chamber slides and allowed to adhere. Following 12 h different treatment, cells from each group were washed with phosphate buffered saline and fixed with 4% formalin for 10 min. Hoechst 33342 was applied for 30 min under dark condition to stain the nuclei of fixed cells. Slides were then washed with phosphate buffered saline and mounted in a mount ing medium, and observed under a fluorescence microscope.

Apoptotic cells were identified as those with a nucleus exhibiting brightly stained condensed chromatin or unclear frag ments. For each experimental condition, four separate cell populations were prepared. Apoptotic indices were deter mined by direct visualization and counting of a minimum of 500 cells per population. The apoptotic index was calcu lated as the ratio of number of apoptotic cells to total cells counted 100. Cell viability assay Cell viability was measured using the MTT dimethylthiahiazo 3,5 diphenytetrazoliumromid assay, based on the MTT conversion into formazan crys tals using mitochondrial dehydrogenases. Briefly, H9c2 cells were plated at a density of 1 104 cells/well in 96 well plates. After different treatment for 12 h, the culture medium was replaced with 200 uL MTT solution. After 4 h incubation at 37 C, this solution was removed and the produced formazan was solubilized in 150 uL dimethyl sulfoxide. The absorbance was measured at 550 nm using an automated microplate reader. Immunoblot Cells were lysed Carfilzomib in ice cold RIPA buffer and the protease of inhibitor phenylmethanesulfonyl fluoride.

On Western blot analysis, phosphorylation of serine 15 seems to b

On Western blot analysis, phosphorylation of serine 15 seems to be re quired for this process. New cancer therapies for patients with mp53 containing tumors are recently being developed. Especially, reports concerning to transfection of p53 gene into tumor and molecules which activate latent p53, change the conformation most of mp53 or restore the function of mp53 are on the increase. We have recently reported that glycerol has an ability to restore normal function to mp53, leading to WAF1 induction. There after, new compounds which rescue mp53 conformation and function have been reported by other laboratory. Among the reported molecules, glycerol is easy to be rec ognized as the most useful molecule for cancer therapy, because it is widely used as a convenient reagent in clini cal course already.

Furthermore, as reported in this paper, glycerol has an ability to enhance bax expression in mp53 cells as a chemical chaperone through phosphorylation of p53 at serine 15 by PI3 K family and conformational change of mp53. Thus, it is expected that the cancer ther apy combined hyperthermia and glycerol is efficient for patients with mp53 containing tumors, in which p53 de pendent bax expression is less frequently induced. As we have reported elsewhere, glycerol is also effec tive in inducing a conformational change of p53 and re storing normal function to mp53, leading to enhanced radiosensitivity. The enhanced radiosensitivity is closely related to the induction of p53 dependent apop tosis. Further, we have recently obtained results showing that glycerol functions as a chemical chaperone in p53 de pendent CDDP sensitivity.

Our re sults obtained from previous and the present studies show that glycerol is available for cancer therapy such as hyper thermia, radiotherapy or chemotherapy which induces the activation of p53 even in mp53 tumors. Materials and Methods Cells Human glioblastoma A 172 cells were cultured at 37?C in Dulbeccos Modified Eagle medium containing 10% fetal bovine serum, penicillin, streptomycin and kan amycin. Plasmids A 172 cells were transfected with the plasmids pC53 SCX3, pC53 248 or pCMV Neo Bam. Be fore transfection, these plasmids were digested with Hin dIII and linearized. A 172 cells were electroporated three times at 600 V with linearized DNA. The transfectants were selected by G418 and incubated at 37?C through all experiments.

Glycerol treatment Cells were treated with glycerol 48 h before heating and then were incubated at 37?C for 6 or 10 h in the presence of glycerol until sampling. In the case Brefeldin_A of cell survival assay, the medi um with glycerol was changed with glycerol free one after 10 h incubation and thereafter cells were incubated for ten to fourteen days at 37?C in glycerol free medium. In in vit ro treatment, whole cell extracts from intact cells were treated with glycerol for 30 min at 37?C.

Extinction of reaction product was measured at 405 nm on Victor3

Extinction of reaction product was measured at 405 nm on Victor3 1420 Multilabel Counter reader. Amounts of generated aPC were calculated using aPC standards and normal ized to cell protein content. Data analysis Data were analyzed by one way analysis of variance coupled with Dunnetts post hoc test to compare each experimental group with a nominated most control group using SPSS 14. 0 software. Differences were considered significant at P 0. 05. Background Epithelial ovarian cancer is the fifth leading cause of cancer death in women and the most lethal gynecolo gic malignancy. In spite of aggressive surgical cytore duction and combination platinum paclitaxel chemotherapy, over 75% of women with stage III IV dis ease will relapse and succumb to their disease.

Resis tance to platinum based therapy is a primary obstacle in the management of advanced OC and novel therapies are required to enhance platinum chemotherapy and to improve prognosis. Hereditary mutations in the Breast Cancer 1 tumor suppressor gene are associated with a significant risk of developing breast and OC. Although somatic mutations in BRCA1 are uncommon in sporadic OC, BRCA1 dysfunction is frequently observed. Silencing of BRCA1, through promoter methylation, decreased expression through gene deletion, or dysregulation of related genes in the Fanconi anemia BRCA1 pathway, is believed to be important in the pathogenesis of a significant proportion of sporadic tumors. Preclinical work has shown that the level of BRCA1 protein expression correlates with chemosensitivity, and recent clinical data supports that BRCA1 deficient OC patients have a better prognosis.

Low BRCA1 protein and mRNA expression has also been associated with improved survival in breast cancer and non small cell lung cancer. The improved outcome in BRCA1 deficient tumors is believed to be due, in part, to an increased sensitivity to DNA damaging che motherapeutics, such as cisplatin. Cells that lack BRCA1 have a deficiency in the repair of double strand breaks by the conservative mechanism of homologous recombination. As a result, these cancer cells are reduced to using error prone pathways thereby lead ing to genomic instability and enhanced cisplatin cyto toxicity. Thus, BRCA1 has been regarded as a rational therapeutic target to help overcome platinum resistance in advanced and recurrent OC.

However, in an era of evolving molecular inhibitors, new therapeutic strategies merit consideration. The interaction between histone acetyl transferases and histone deacetylase enzymes modulates chromatin structure and transcription factor accessibil ity, resulting Brefeldin_A in changes in gene expression. Inhibi tors of HDAC have pleiotropic effects on cell cycle arrest, apoptosis, differentiation and inhibition of growth and angiogenesis, and have emerged as promis ing new therapeutic agents in multiple cancers, includ ing those resistant to standard chemotherapy.

Accordingly, we hypothesized HDACi induced increases in b catenin

Accordingly, we hypothesized HDACi induced increases in b catenin stabilization and nuclear localization accounted for Olig2 suppres sion in our cell fate assays. However Western dilution calculator blot ana lysis failed to detect significant differences in nuclear protein levels of b catenin in adult mouse NSCs trea ted with HDACi under proliferation culture conditions. We speculate HDACi effects on other targets offset this competitive interaction. One possible candidate is Hdac6, a class IIb HDAC. Hdac6 deacetylates b cate nin at lysine 49 to reduce b catenin phosphor ylation and promote b catenin nuclear localization and c myc induction. Thus inhibition of Hdac1 2 and Hdac6 activity has the capacity to promote opposing effects on b catenin stability and nuclear localization by increasing stability via inhibition of Hdac1 2 as well as decreasing stability and nuclear localization as a result of increased Lys49 acetylation and phosphorylation.

Indeed differential sensitivities of Hdac1 2 and Hdac6 to SAHA and NaB inhibition might underlie the different fold changes in b catenin nuclear localization compared to vehicle controls. The fact that the effects of HDACi are con sistent with anti proliferative responses to pharmacolo gical and genetic interventions targeting the canonical Wnt b catenin signaling pathway in adult NSCs suggests the net effect of these molecules is to inhibit rather than activate this signaling pathway. Conclusion In summary, the broad class I and class II HDAC inhi bitors SAHA and NaB blocked G1 to S phase progres sion in proliferating adult NSCs in vitro.

Gene expression changes induced by SAHA and NaB treat ment in adult NSCs vary in fold change but not direc tionality, consistent with the comparable treatment outcomes of G1 arrest. In addition, the direction of gene changes induced by SAHA and NaB treatment is consistent with G1 arrest accompanied by a reduction of stem progenitor state and activation of neuronal lineage commitment programs. SAHA and NaB treat ment induces increases in the transcription of Cdk inhibitors p21 and p27 in adult NSCs which was asso ciated with elevated H3K9 acetylation levels at proxi mal promoter regions. This association is consistent with direct SAHA and NaB effects on cell cycle arrest genes in adult NSCs, in common with widely reported HDACi induced growth arrest in normal and trans formed cells.

Finally, we show HDACi treat ment under proliferation culture conditions leads to long term changes in cell fate in adult NSCs induced to differentiate in vitro. Methods Animals 8 10 week old male and female C57BL 6J mice were purchased from The Jackson Laboratory and housed in the Uniformed Services Universitys Cen ter for Laboratory Animal Medicine prior to experimen tal use. Batimastat Animals were handled in accordance with procedures approved by the Uniformed Services Univer sity of the Health Sciences Institutional Animal Care and Use Committee.

The gcn5 strain shows increased cell death after 1 h, whereas cel

The gcn5 strain shows increased cell death after 1 h, whereas cell death in the wild type strain increases significantly after 2 h. By 4 h propidium iodide uptake is detectable in 6. 7% of the wild type population, compared to 16. 6% of the gcn5 population. Discussion The global decrease in histone modification, particularly methylation and acetylation correlates nearly with an aggressive phenotype and poor prognosis in a number of cancers including prostate, lung and kidney cancer. The ability of HDACis to induce death in a variety of cell lines is well documented, however the mechanisms by which they exert their effects are incompletely under stood. Since many biological processes are regu lated by acetylation, we have used a yeast deletion library screen to gain insights into the cell growth inhibition mechanisms of HDAC inhibitors and to iden tify novel targets for combination treatments with the HDACi CG 1521.

Choosing S. cerevisiae as a model or ganism decreases the complexity, however the high de gree of functional homology among eukaryotes enables the identification of pathways that are important in the response to CG 1521. For example, mitotic analysis after exposure to TSA shows disruption of centromeric het erochromatin, mitotic delay and chromosome segrega tion defects in both fission yeast and mammalian cells. Eukaryotic cells have varied responses to HDACis, which in mammalian cells is partially dictated by the p53 status of the cell lines. For example, treat ment of LNCaP prostate cancer cells, which express wild type p53, with CG 1521 induces G2 M arrest and apoptosis.

In contrast, TSA induces G1 S arrest. These differences in biological response have been attributed to differences in the site specific acetylation of p53, stabilized by these two drugs. However, MCF 7 breast cancer cells, which express wild type p53 and SUM190PT, which express mutant p53 both arrest in G0 G1 after treatment with either CG 1521 or TSA, sug gesting that the complement of HDACs present in the cells also plays a significant role in dictating the bio logical outcome of treatment. Despite the roles of histone acetyltransferases and histone deacetylases in DNA replication and DNA re pair, cytoskeleton dynamics and cell cycle, these func tional classes are not significantly enriched in our screen.

However CG 1521 sensitive strains are significantly enriched in vesicle mediated transport, endocytosis and sensitive to CG 1521. Potentially, these CG 1521 sensitive strains are characterized by decreased histone acetylation and Gcn5 HAT activity as well. This suggests that disrupting the dynamics of acetylation and deacety lation Anacetrapib renders cells sensitive to CG 1521. Strains lacking components of the Gcn5 HAT complexes are very sensitive to CG 1521. Deletion of any of the four components of the histone acetyltransferase module renders S.