Generation Deep Sequencing Research Articles

TGFβ1 increases oxidative stress in human osteoarthritis articular chondrocytes through mechanisms involving NOX4

TGFβ1 increases oxidative stress in human osteoarthritis articular chondrocytes through mechanisms involving NOX4

Restriction of V3 region sequence divergence in the HIV-1 envelope gene during antiretroviral treatment in a cohort of recent seroconverters

BackgroundDynamic changes in Human Immunodeficiency Virus 1 (HIV-1) sequence diversity and divergence are associated with immune control during primary infection and progression to AIDS. Consensus sequencing or single genome amplification sequencing of the HIV-1 envelope (env) gene, in particular the variable (V) regions, is used as a marker for HIV-1 genome diversity, but population diversity is only minimally, or semi-quantitatively sampled using these methods.ResultsHere we use second generation deep sequencing to determine inter-and intra-patient sequence heterogeneity and to quantify minor variants in a cohort of individuals either receiving or not receiving antiretroviral treatment following seroconversion; the SPARTAC trial. We show, through a cross-sectional study of sequence diversity of the env V3 in 30 antiretroviral-naive patients during primary infection that considerable population structure diversity exists, with some individuals exhibiting highly constrained plasma virus diversity. Diversity was independent of clinical markers (viral load, time from seroconversion, CD4 cell count) of infection. Serial sampling over 60 weeks of non-treated individuals that define three initially different diversity profiles showed that complex patterns of continuing HIV-1 sequence diversification and divergence could be readily detected. Evidence for minor sequence turnover, emergence of new variants and re-emergence of archived variants could be inferred from this analysis. Analysis of viral divergence over the same time period in patients who received short (12 weeks, ART12) or long course antiretroviral therapy (48 weeks, ART48) and a non-treated control group revealed that ART48 successfully suppressed viral divergence while ART12 did not have a significant effect.ConclusionsDeep sequencing is a sensitive and reliable method for investigating the diversity of the env V3 as an important component of HIV-1 genome diversity. Detailed insights into the complex early intra-patient dynamics of env V3 diversity and divergence were explored in antiretroviral-naïve recent seroconverters. Long course antiretroviral therapy, initiated soon after seroconversion and administered for 48 weeks, restricts HIV-1 divergence significantly. The effect of ART12 and ART48 on clinical markers of HIV infection and progression is currently investigated in the SPARTAC trial.

SRY mutation analysis by next generation (deep) sequencing in a cohort of chromosomal Disorders of Sex Development (DSD) patients with a mosaic karyotype

BackgroundThe presence of the Y-chromosome or Y chromosome-derived material is seen in 4-60% of Turner syndrome patients (Chromosomal Disorders of Sex Development (DSD)). DSD patients with specific Y-chromosomal material in their karyotype, the GonadoBlastoma on the Y-chromosome (GBY) region, have an increased risk of developing type II germ cell tumors/cancer (GCC), most likely related to TSPY. The Sex determining Region on the Y gene (SRY) is located on the short arm of the Y-chromosome and is the crucial switch that initiates testis determination and subsequent male development. Mutations in this gene are responsible for sex reversal in approximately 10-15% of 46,XY pure gonadal dysgenesis (46,XY DSD) cases. The majority of the mutations described are located in the central HMG domain, which is involved in the binding and bending of the DNA and harbors two nuclear localization signals. SRY mutations have also been found in a small number of patients with a 45,X/46,XY karyotype and might play a role in the maldevelopment of the gonads.MethodsTo thoroughly investigate the presence of possible SRY gene mutations in mosaic DSD patients, we performed next generation (deep) sequencing on the genomic DNA of fourteen independent patients (twelve 45,X/46,XY, one 45,X/46,XX/46,XY, and one 46,XX/46,XY).Results and conclusionsThe results demonstrate that aberrations in SRY are rare in mosaic DSD patients and therefore do not play a significant role in the etiology of the disease.

Single Molecule Real Time (SMRT™) Sequencing Sensitively Detects the Evolution of Polyclonal and Compound BCR-ABL Mutations in Patients Who Relapse On Kinase Inhibitor Therapy

AbstractAbstract 917 Background:Secondary kinase domain (KD) mutations represent the most well-documented mechanism of resistance to tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML). In CML, multiple TKIs with different mutation profiles are approved and the ability to detect KD mutations at the time of disease progression can impact therapy choice. To optimize clinical impact, second generation TKI selection must consider the majority TKI-resistant mutant population as well as smaller mutant sub-populations that may be selected with subsequent treatment. Sequential TKI therapy is associated with additional complexity: multiple mutations can coexist separately in an individual patient (“polyclonality”) or can occur in tandem on a single allele (“compound mutations”). Multiple mutations are associated with poor clinical outcome (Parker et al., Blood 2012). Compound mutations can cause in vitro resistance to ponatinib, the only TKI clinically active against the highly resistant T315I mutation (Eide, et. al, ASH 2012 abstract #1416). Currently, no clinically adaptable technology can distinguish polyclonal from compound mutations. Due to the size of the BCR-ABL KD, most next-generation sequencing platforms cannot generate reads of sufficient length to determine if mutations separated by ≥500 nt reside on the same allele. Pacific Biosciences RS Single Molecule Real Time (SMRT) sequencing technology is a third generation deep sequencing technology capable of achieving average read lengths of ∼1000bp and frequently >3000bp, enabling sensitive and accurate sequencing of the entire ABL KD on a single strand of DNA. Though allele-specific detection methods such as MassARRAY offer sensitivity as low as ∼0.5%, these assays are designed to detect a limited number (∼31) of mutations whereas SMRT sequencing offers an unbiased approach capable of detecting novel variants. We sought to (1) develop a potential clinically-applicable SMRT sequencing assay for the detection of BCR-ABLKD mutations capable of distinguishing polyclonal and compound mutations, and (2) compare the accuracy and sensitivity of this method to standard sequencing and MassARRAY. Results:We assessed 54 samples from 36 CML patients who had clinically relapsed on ABL kinase inhibitor therapy and were previously analyzed by standard sequencing, and in a subset, by MassARRAY. We amplified an 863bp area of the BCR-ABLKD from patient-derived cDNA with primers containing 5’ barcodes, enabling sequencing of 6 to 8 patient samples on a single SMRT cell on a single run. On average, 2519 reads were obtained for each sample per run (range 330 to 10,240). All of 131 known mutations detected by MassARRAY were identified by SMRT sequencing using a p-value threshold of 1.03e–03. SMRT sequencing also identified all 107 known mutations detected by direct sequencing with a p-value threshold of 6.0e–08. In addition to these known mutations, SMRT sequencing detected an additional 1320 non-silent mutations across all patient samples using a strict p-value threshold cut-off of 6e–08, ranging in abundance from 0.2% to 17% (median 0.75%). Among 47 samples where >1 mutation was detectable by direct sequencing or MassARRAY, SMRT sequencing revealed that 40 (85%) had compound mutations detectable at a frequency of ≥1. In total, we detected 73 different compound mutations at a frequency of ≥1%. In all cases where compound mutations were detected and more than one treatment timepoint was available, at least one compound mutation clearly evolved from a mutation detectable at a prior timepoint. In the most complex case, 4 separate mutations yielded 8 different mutant alleles. Conclusions:Pacific Biosciences RS SMRT sequencing detects KD mutations in patient samples with sensitivity comparable to or better than MassARRAY and can distinguish compound from polyclonal mutant clones. Among patient samples with multiple mutations, compound mutations were detectable in the vast majority of samples by SMRT sequencing, revealing a complex mutational landscape not demonstrable by other clinically viable sequencing methods and previously unappreciated. Given the growing numbers of patients exposed to multiple TKIs in a sequential manner, the ability to accurately and sensitively characterize drug-resistant alleles by SMRT sequencing promises to further facilitate a personalized approach to patient management and inform models of disease evolution. Disclosures:Brown:Pacific Biosciences: Employment. Travers:Pacific Biosciences: Employment. Wang:Pacific Biosciences: Employment. Branford:Novartis : Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Ariad : Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cepheid : Consultancy. Shah:ARIAD, Bristol Myers-Squibb: Consultancy, Research Funding; Novartis: Consultancy.

Loss of Heterozygosity At the C Wild-Type Allele of rs1042522 in the TP53 Gene Frequently Occurs During Progression of Adult BCR-ABL1 Positive Acute Lymphoblastic Leukemia (ALL).

Abstract 2497 Introduction:The gene TP53 encoding the tumour suppressor protein p53 is among the most commonly mutated genes in human cancer. TP53 tumour-associated alterations often cause dramatic defects in p53 function and correlate with increased malignancy, dismal survival and resistance to treatment. In contrast, only a small fraction, if any, of the >200 single nucleotide polymorphisms (SNPs) of TP53 in human populations are expected to cause measurable perturbation of p53 function. Aim:Since the pattern, frequency and significance of TP53 aberrations and SNPs in adult BCR-ABL1 positive ALL have still to be investigated, in this study we used a massively parallel pyrosequencing technique to address these issues. Patients and methods:Forty-three adults with BCR-ABL1 positive ALL were analyzed (median age 63 years, range 18–84). Twenty-four cases (56%) were analyzed only at the time of diagnosis, four cases (9%) only at the time of relapse and fifteen cases (35%) at both time points. Massively parallel pyrosequencing in picoliter-sized wells was used to allow highly-sensitive deep-sequencing detecting molecular aberrations at a low burden rate. As part of the IRON (Interlaboratory RObustness of Next generation sequencing) II study network, we applied preconfigured plates including primers for TP53 (exons 4 to 11) and allowing the simultaneous screening of 11 patients, each being recognized by a unique molecular identifier. For each plate, after generating 88 amplicons, 8 per each patient, PCR products were purified using Agencourt AMPure XP beads and Biomek 3000 Laboratory Automation Workstation (Beckam Coulter) and quantified using the Quant-iT PicoGreen kit (Invitrogen). All amplicons were pooled in an equimolar ratio to generate one single library. Subsequent emulsion PCR and amplicon sequencing was performed according to the manufacturer’s recommendations on the Genome Sequencer Junior Instrument (Roche Applied Science). Data were analyzed using the GS Amplicon Variant Analyzer software version 2.7 (Roche Applied Science). For the detection of variances, filters were set to display sequence variances occurring in more than 5% of bidirectional reads per amplicon in at least one sample. Results:On average, we generated 63,068 sequencing beads (key pass wells) per plate (range, 50,798-79,486) with a median read length range between 284 and 365 base pairs. The median number of generated reads per case was 5,413 (range, 687-9,604). The median number of reads per amplicon was as follows: exon 4: 275 (range, 0–888), exon 5: 222 (range, 0–1,013); exon 6: 316 (range, 84–854); exon 7: 317 (range, 5–720); exon 8: 313 (range, 0–784); exon 9: 215 (range, 0–785); exon 10: 328 (range, 0–826), exon 11: 447 (range, 0–1,511). Forward and reverse reads were homogeneously distributed allowing a sensitive detection of variances. In total, 8 single nucleotide variations were identified. All variances, except for one nucleotide substitution occurring at position 7576743 (GRCh37/hg19), were found to represent SNPs according to the NCBI dbSNP Build 137. They included: rs1042522 C/G (41/43, 95%) and rs1800370 A/G (1/43, 2%) in exon 4, rs1800372 A/G (2/43, 5%) in exon 6, rs1625895 A/G (42/43, 98%) in intron 6–7, rs12947788 A/G (3/43, 7%) and rs12951053 A/C (4/43, 9%) in intron 7–8 and rs1800899 C/T (1/43, 2%) in intron 9–10. Interestingly, in 2 cases (12%) loss of heterozygosity occurred at the relapse at the C wild-type allele of rs1042522 in leukemia cells. The same mechanism has been identified for one case at the wild-type allele of rs1625895 with the expansion of the variant form at relapse. Both rs1042522 and rs1625895 have been described to alter p53 functionality and increase susceptibility to cancers (Whibley et al.,2009). Although the role of rs12947788 and rs12951053 has not yet deeply investigated, in our study they were found in 3 cases that all relapsed. Conclusion:Comprehensive next generation deep-sequencing of TP53 by a screening assay set up within the IRON II study has demonstrated its ability to efficiently detect TP53 variant. The inactivation of the wild-type allelic forms of rs1042522 and rs1625895, altering the p53 functionality, may serve as an important background for leukemia progression in BCR-ABL1-positive ALL. Disclosures:Kohlmann:MLL Munich Leukemia Laboratory: Employment. Luppi:CELGENE CORPORATION: Research Funding. Haferlach:MLL Munich Leukemia Laboratory: Equity Ownership. Baccarani:ARIAD, Novartis, Bristol Myers-Squibb, and Pfizer: Consultancy, Honoraria, Speakers Bureau. Martinelli:NOVARTIS: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; PFIZER: Consultancy; ARIAD: Consultancy.

Genome-Wide MicroRNA Expression Analysis of Clear Cell Renal Cell Carcinoma by Next Generation Deep Sequencing

MicroRNAs (miRNAs), non-coding RNAs regulating gene expression, are frequently aberrantly expressed in human cancers. Next-generation deep sequencing technology enables genome-wide expression profiling of known miRNAs and discovery of novel miRNAs at unprecedented quantitative and qualitative accuracy. Deep sequencing was performed on 11 fresh frozen clear cell renal cell carcinoma (ccRCC) and adjacent non-tumoral renal cortex (NRC) pairs, 11 additional frozen ccRCC tissues, and 2 ccRCC cell lines (n = 35). The 22 ccRCCs patients belonged to 3 prognostic sub-groups, i.e. those without disease recurrence, with recurrence and with metastatic disease at diagnosis. Thirty-two consecutive samples (16 ccRCC/NRC pairs) were used for stem-loop PCR validation. Novel miRNAs were predicted using 2 distinct bioinformatic pipelines. In total, 463 known miRNAs (expression frequency 1–150,000/million) were identified. We found that 100 miRNA were significantly differentially expressed between ccRCC and NRC. Differential expression of 5 miRNAs was confirmed by stem-loop PCR in the 32 ccRCC/NRC samples. With respect to RCC subgroups, 5 miRNAs discriminated between non-recurrent versus recurrent and metastatic disease, whereas 12 uniquely distinguished non-recurrent versus metastatic disease. Blocking overexpressed miR-210 or miR-27a in cell line SKCR-7 by transfecting specific antagomirs did not result in significant changes in proliferation or apoptosis. Twenty-three previously unknown miRNAs were predicted in silico. Quantitative genome-wide miRNA profiling accurately separated ccRCC from (benign) NRC. Individual differentially expressed miRNAs may potentially serve as diagnostic or prognostic markers or future therapeutic targets in ccRCC. The biological relevance of candidate novel miRNAs is unknown at present.

Editorial [Hot Topic: Genetics Dissection of Complex Traits in the Genomic Era (Guest Editor: Bernardo Ordas)

Editorial [Hot Topic: Genetics Dissection of Complex Traits in the Genomic Era (Guest Editor: Bernardo Ordas)

Development of a porcine (Sus scofa) embryo-specific microarray: array annotation and validation

BackgroundThe domestic pig is an important livestock species and there is strong interest in the factors that affect the development of viable embryos and offspring in this species. A limited understanding of the molecular mechanisms involved in early embryonic development has inhibited our ability to fully elucidate these factors. Next generation deep sequencing and microarray technologies are powerful tools for delineation of molecular pathways involved in the developing embryo.ResultsHere we present the development of a porcine-embryo-specific microarray platform created from a large expressed sequence tag (EST) analysis generated by Roche/454 next-generation sequencing of cDNAs constructed from critical stages of in vivo or in vitro porcine preimplantation embryos. Two cDNA libraries constructed from in vitro and in vivo produced preimplantation porcine embryos were normalized and sequenced using 454 Titanium pyrosequencing technology. Over one million high-quality EST sequences were obtained and used to develop the EMbryogene Porcine Version 1 (EMPV1) microarray composed of 43,795 probes. Based on an initial probe sequence annotation, the EMPV1 features 17,409 protein-coding, 473 pseudogenes, 46 retrotransposed, 2,359 non-coding RNA, 4,121 splice variants in 2,862 genes and a total of 12,324 Novel Transcript Regions (NTR). After re-annotation, the total unique genes increased from 11,961 to 16,281 and 1.9% of them belonged to a large olfactory receptor (OR) gene family. Quality control on the EMPV1 was performed and revealed an even distribution of ten clusters of spiked-in control spots and array to array (dye-swap) correlation was 0.97.ConclusionsUsing next-generation deep sequencing we have produced a large EST dataset to allow for the selection of probe sequences for the development of the EMPV1 microarray platform. The quality of this embryo-specific array was confirmed with a high-level of reproducibility using current Agilent microarray technology. With more than an estimated 20,000 unique genes represented on the EMPV1, this platform will provide the foundation for future research into the in vivo and in vitro factors that affect the viability of porcine embryos, as well as the effects of these factors on the live offspring that result from these embryos.

IMGT/HIGHV-QUEST: THE IMGT® WEB PORTAL FOR IMMUNOGLOBULIN (IG) OR ANTIBODY AND T CELL RECEPTOR (TR) ANALYSIS FROM NGS HIGH THROUGHPUT AND DEEP SEQUENCING

BACKGROUND The number of antigen receptors, immunoglobulins (IG) or antibodies and T cell receptors (TR) of the adaptive immune response in vertebrates with jaws is almost unlimited (2.10 12 per individual in humans). This huge diversity results from complex mechanisms in the synthesis of the variable (V) domains, that include DNA molecular rearrangements of the V, diversity (D) and joining (J) genes, N-diversity at the V-(D)-J junctions and, for IG, somatic hypermutations. The specificity of the V domains is conferred by the complementarity determining regions (CDR) and more particularly the CDR3. IMGT®, the international ImMunoGeneTics information system®, has developed online tools that provide a detailed and accurate sequence analysis of the V domains (IMGT/V-QUEST) and CDR3 (IMGT/JunctionAnalysis), based on IMGT-ONTOLOGY. However online analyses are limited to 50 sequences per batch. The challenge was to provide identical high quality analysis for the huge number of sequences obtained by Next Generation Sequencing (NGS) high throughput and deep sequencing. Results IMGT® has developed IMGT/HighV-QUEST that analyses up to 150,000 IG or TR V domain sequences per batch and performs statistical analysis on the results of up to 450,000 sequences. IMGT/HighV-QUEST provides users with: (i) a friendly web interface for submission and results retrieval, (ii) high quality detailed results of IMGT/V-QUEST and IMGT/JunctionAnalysis, based on the IMGT-ONTOLOGY concepts and IMGT Scientific chart rules, (iii) a standardized frame for NGS statistical analysis, based on ‘Results category’ (‘1 copy’, ‘More than 1’, ‘single allele’, ‘several alleles (or genes)’, (iv) detailed standardized statistical analysis tables and histograms (e.g., V, D and J usage, CDR3-IMGT lengths). Conclusions

PD01-09: Identifying Novel Mechanisms of Resistance to Lapatinib in ERBB2+ Breast Cancer Cells through Whole Genome Mutational Analysis.

Abstract Background: Overexpression of the epidermal growth factor receptor ERBB2 (HER2) is found in 20% of human breast cancers. Therapies targeting ERBB2 including trastuzumab and lapatinib have significantly improved the outlook for women with ERBB2+ breast cancer. However, resistance to these agents occurs frequently and remains a significant clinical problem. In the case of lapatinib resistance, the mechanism(s) of resistance remain poorly understood, since the current proposed rationale thought to limit lapatinib's anti-tumor effects has been difficult to reconcile with clinical data. Therefore, we hypothesize that novel mechanisms of resistance could be identified by mapping genomic variations in ERBB2+ cells with acquired resistance to lapatinib. The identification of such mutations may provide insights into mechanisms of resistance and may indicate therapeutic strategies to overcome lapatinib resistance in ERBB2+ breast cancer. Material and Methods: SKBR3 breast cancer cells resistant to lapatinib were generated through serial passage by exposure of drug sensitive parental SKBR3 cells to increasing concentrations of lapatinib up to the peak plasma concentration observed in human subjects (2.6 uM (SK-lapR)). Multiple signaling pathways in lapatinib sensitive and resistant cells were interrogated by Reverse Phase Protein Array (RPPA) and western blot analysis. To identify genome wide somatic mutations, the Exome of lapatinib resistant and sensitive SKBR3 cells was sequenced utilizing next generation deep sequencing. Following exclusion of germline variants, the acquired gene mutations in lapatinib resistant SKBR3 cells were confirmed by DNA re-sequencing of PCR amplified DNA segments. Results and Discussion: Analysis of activated signaling pathways in lapatinib resistant and sensitive SKBR3 cells did not confirm any of the previously proposed mechanisms of resistance. In particular, these cells show no activation of AKT or alternative receptor tyrosine kinases such as IGF-IR, ERBB3 or c-Met. However they exhibit sustained activation of mTORC1 and ERK1/2, as well as phosphorylation of STAT3, STAT5, rpS6 and CREB. Initial sequence analysis of exome and transcriptome reveals the presence of 76 single nucleotide variants/Indels differing between sensitive and resistant cells with 34/76 validated as true mutations present in the genome of lapatinib resistant SKBR3 cells, including mutations in LATS2, MAP3K5, SMAD3 and PDGFRA. This is the first exome sequence analysis to be reported which defines a drug resistant phenotype in ERBB2+ breast cancer. Ongoing work includes investigation of mutations as drug resistance mediators and analysis of copy number variations and gene fusions/translocations to systematically search for molecular alterations, with the goal of providing a rationale for the design of new combination therapies aimed at lapatinib resistance for ERBB2+ breast cancer. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD01-09.

Single Molecule Real Time (SMRT™) Sequencing Sensitively Detects Polyclonal and Compound BCR-ABL in Patients Who Relapse on Kinase Inhibitor Therapy,

Abstract 3752 Background:Secondary kinase domain (KD) mutations are the most well-recognized mechanism of resistance to tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML) and other cancers. In some cases, multiple drug resistant KD mutations can coexist in an individual patient (“polyclonality”). Alternatively, more than one mutation can occur in tandem on a single allele (“compound mutations”) following response and relapse to sequentially administered TKI therapy. Distinguishing between these two scenarios can inform the clinical choice of subsequent TKI treatment. There is currently no clinically adaptable methodology that offers the ability to distinguish polyclonal from compound mutations. Due to the size of the BCR-ABL KD where TKI-resistant mutations are detected, next-generation platforms are unable to generate reads of sufficient length to determine if two mutations separated by 500 nt reside on the same allele. Pacific Biosciences RS Single Molecule Real Time (SMRT) circular consensus sequencing technology is a novel third generation deep sequencing technology capable of rapidly and reliably achieving average read lengths of ∼1000bp (Travers et al, 2010) and frequently beyond 3000bp, allowing sequencing of the entire ABL KD on single strand of DNA. We sought to address the ability of SMRT sequencing technology to distinguish polyclonal from compound mutations using clinical samples obtained from patients who have relapsed on BCR-ABL TKI treatment. Results:We analyzed an 863bp area of the BCR-ABL KD in 6 patients who had clinically relapsed on ABL kinase inhibitor therapy. SMRT sequencing detected mutations at a sensitivity of ∼1–2% of the total sequenced population, and successfully distinguished polyclonal from compound BCR-ABL KD mutations in several patient samples. Results were largely consistent with those obtained by PCR subcloning and sequencing, although SMRT sequencing detected additional mutations and/or mutation combinations. In the most complex case, 7 distinct mutation-bearing alleles were detected in an individual patient after sequential relapse on imatinib and dasatinib. Mutant clones contained single and compound mutations combining distinct mutations (Y253H, T315F, T315A, T315I, T319A, E355G). Three distinct substitutions at residue T315 were detected: T315A, T315I and T315F. Notably, these findings are clinically important as the T315A mutation confers resistance to dasatinib but not imatinib, while the T315F and T315I mutations are resistant to all three clinically approved BCR/ABL inhibitors (imatinib, dasatinib, and nilotinib). Phospho-flow analysis for p-Crkl, a direct substrate of BCR-ABL, was conducted following ex vivo exposure of patient cells from the same time point to all three BCR-ABL inhibitors, and demonstrated the existence of distinct populations of cells with varying sensitivity to each drug (i.e. polyclonal drug sensitivity), underscoring the potential clinical importance of distinguishing polyclonal from compound mutations. Additionally, SMRT sequencing routinely detected alleles harboring compound mutations not detectable by conventional direct sequencing. Data analysis of samples from additional patients is ongoing and will be presented. Conclusions:Pacific Biosciences RS SMRT sequencing sensitively detects KD mutations in patient samples and can distinguish TKI-resistant clones containing compound mutations to reveal a complex mutational landscape in an individual patient not detectable by conventional sequencing. SMRT sequencing of the BCR-ABL KD can feasibly be developed into a rapid and economical clinical test with the additional advantages of increased sensitivity and reliability over current methods. Given the growing numbers of patients exposed to multiple TKIs in a sequential manner, the ability to accurately and sensitively characterize drug-resistant alleles promises to further facilitate a personalized approach to patient management. Disclosures:Brown:Pacific Biosciences: Employment. Chin:Pacific Biosciences: Employment. Travers:Pacific Biosciences: Employment. Wang:Pacific Biosciences: Employment. Kasarskis:Pacific Biosciences: Employment, Equity Ownership. Schadt:Pacific Biosciences: Employment, Equity Ownership.

Defining the genetic blueprint of kidney development

Thousands of genes show differential expression patterns during kidney development, suggesting that the genetic program driving this process is complex. While great progress has been made in defining the outline of the genetic basis of nephrogenesis, it is clear that much remains to be learned. A global atlas of the gene expression profiles of the multiple elements of the developing kidney would allow the identification of novel growth factor-receptor interactions, identify additional molecular markers of distinct components, facilitate the generation of compartment specific GFP-CRE transgenic mouse tools, lend insights into the genetic regulatory circuits governing nephron formation, and fully characterize the waves of gene expression that impel nephrogenesis. Both microarrays and next generation deep sequencing of cDNA libraries can be used to define comprehensive, sensitive, and quantitative gene expression profiles. In addition, laser capture microdissection and transgenic GFP mice can be used to isolate specific compartments and pure cell types from the developing kidney. Advancing technologies are even allowing robust gene expression profiling of single cells. The final goal is the production of an exquisitely detailed atlas of the gene expression program that drives kidney development.

Whole genome deep sequencing from single cells for preimplantation genetic diagnosis

FISH and PCR are two main methodologies being used for preimplantation genetic diagnosis (PGD) in the last two decades. Recent advancements in micro-array technology expand the applications of PGD, particularly for preimplatation genetic screening (PGS) to 24 chromosome analysis. A much more powerful approach, next generation sequencing (NGS), is emerging and may have the potential to replace current methodologies for comprehensive genetic analysis. The purpose of this study was to prove the concept that NGS for whole genome analysis on the amplified products from single cells can be used for chromosome copy number assessment and single gene disorder detection. Proof of concept. The whole genome of single cells from known fibroblast cell lines was amplified using commercially available kits. Libraries from amplified DNA were prepared and shotgun deep sequencing was performed using the Roche 454 (Junior) platform. Reads were assembled and aligned using a publically available sequence (Nature, 2008; 456:60) and were analyzed with BWA-SW algorithm. Copy number variation (CNV) was analyzed with MATLAB SegSeq software. NGS on whole genome amplified products from single cells successfully detected the chromosome permutations in cell lines with chromosomal abnormalities. In the experiments we performed, a single NGS run could generate more than one hundred thousand reads, with an average length of 363bp. Computational analysis of the reads indicated the known genetic mutations could be detected. This work indicates that next generation deep sequencing provides high sensitivity and coverage for single cell comprehensive genetic analysis. Thus proves unequivocally that NGS will be a viable technique for clinical PGD in the near future. The method's limitations that exist today, such as speed and cost, are expected to be eliminated in the coming years.

Observations on potential novel transcripts from RNA-Seq data

With the rapid development of next generation deep sequencing technologies, sequencing cDNA reverse-transcribed from RNA molecules (RNA-Seq) has become a key approach in studying gene expression and transcriptomes. Because RNA-Seq does not rely on annotation of known genes, it provides the opportunity of discovering transcripts that have not been annotated in current databases. Studying the distribution of RNASeq signals and a systematic view on the potential new transcripts revealed from the signals is an important step toward the understanding of transcriptomes.

Glucocorticoids Modulate MicroRNA Expression and Processing during Lymphocyte Apoptosis

Glucocorticoids modulate immune development and function through the induction of lymphocyte apoptosis via mechanisms requiring alterations in gene expression. Recently, short, noncoding, microRNAs have been identified as key regulators of lymphocyte function; however, it is unknown whether glucocorticoids regulate noncoding microRNAs and whether this regulation contributes to lymphocyte apoptosis. We now show by both microarray and deep sequencing analysis that microRNAs are substantially repressed during glucocorticoid-induced apoptosis of primary rat thymocytes. Mechanistic studies revealed that primary microRNA transcripts were not repressed, whereas the expression of the key microRNA processing enzymes: Dicer, Drosha, and DGCR8/Pasha, were significantly reduced at both the mRNA and protein levels during glucocorticoid-induced apoptosis. To delineate the role of Dicer depletion and microRNA repression in apoptosis, we silenced Dicer expression in two human leukemic cell lines and demonstrated that Dicer depletion significantly enhanced glucocorticoid-induced apoptosis in both model systems. Finally, in vitro and in vivo overexpression of the conserved miR-17-92 polycistron, which was repressed significantly by dexamethasone treatment in both our microarray and deep sequencing studies, blunted glucocorticoid-induced apoptosis. These studies provide evidence of altered post-transcriptional microRNA expression and the repression of the microRNA bioprocessing pathway during glucocorticoid-induced apoptosis of lymphocytes, suggesting a role for microRNA processors and specific microRNAs in cell life/death decisions.