Project description:We sequenced insertion sites for the maize Mutator (Mu) transposon in leaf, root, endosperm, and pollen from Mu-active plants and Mu-inactive controls. Inherited insertions were identified using matched tissues, and then the abundance of de novo (post-zygotic) insertions was quantified and converted to variant allele frequencies (VAF). This dataset provides insight into the abundance of new transposon insertions within heterogeneous tissues and factors that shape mutation accumulation in multicellular organisms.
Project description:Mu transposon insertions were sequenced in the parents and offspring from 4 maize families using MuSeq2. Male parents were Mu-active while female parents were Mu-inactive, and so all new transposon activity can be associated with the male parent. Matched endosperm and leaf from each offspring were sequenced, allowing inherited insertions to be unambiguously identified as these tissues diverge prior to fertilization (each is derived from a sister sperm cell in pollen during double fertilziation). The data were analyzed to follow the transmission of de novo Mu insertions from parent to offspring.
Project description:MuDR/Mu are a highly active transposon family moving by either cut only (or cut-and-paste) in strictly somatic tissues or net replicative transposition (absence of excision alleles) in reproductive tissues. Aside from the MuDR-encoded MURA and MURB proteins, other factors required for Mu transposition, particularly those contributing to the developmentally specific behavior, have yet to be identified. To address this question and assess the impact of a highly active transposon on the transcriptome, RNA was extracted from anthers at three developmental stages in Mu-active and -inactive stocks and compared on a 44,000 element oligonucleotide array. We found that approximately 30,000 unique genes are expressed at each stage. Of the ~10% (ca. 3000) differentially regulated transcripts per stage, there was approximately equal representation by the active or inactive individuals. Keywords: anther development, maize, Mu, transposon
Project description:Genomic DNA from pools of H. pylori strain G27 Clones as indicated (pools of 300 (300p) or insertions in specific mapped genes) were amplifed using the MATT method to label DNA adjacent to the site of transposon insertion with the primer pairs indicated. The left side of the transposon was labeled in the Cy3 channel (Primer S) and the right side of the transposon was labeled in the Cy5 channel (Primer N). Computed
Project description:Genomic DNA from pools of H. pylori strain G27 Clones as indicated (pools of 300 (300p) or insertions in specific mapped genes) were amplifed using the MATT method to label DNA adjacent to the site of transposon insertion with the primer pairs indicated. The left side of the transposon was labeled in the Cy3 channel (Primer S) and the right side of the transposon was labeled in the Cy5 channel (Primer N). Keywords: reference_design
Project description:Somatic transposon mutagenesis in mice is an efficient strategy to investigate the genetic mechanisms of tumorigenesis. The identification of tumor driving transposon insertions traditionally requires the generation of large tumor cohorts to obtain information about common insertion sites. Tumor driving insertions are also characterized by their clonal expansion in tumor tissue, a phenomenon that is facilitated by the slow and evolving transformation process of transposon mutagenesis. We describe here an improved approach for the detection of tumor driving insertions that assesses the clonal expansion of insertions by quantifying the relative proportion of sequence reads obtained in individual tumors. To this end, we have developed a protocol for insertion site sequencing that utilizes acoustic shearing of tumor DNA and Illumina sequencing. We analyzed various solid tumors generated by PiggyBac mutagenesis and for each tumor >10^6 reads corresponding to >10^4 insertion sites were obtained. In each tumor, 9 to 25 insertions stood out by their enriched sequence read frequencies when compared to frequencies obtained from tail DNA controls. These enriched insertions are potential clonally expanded tumor driving insertions, and thus identify candidate cancer genes. The candidate cancer genes of our study comprised many established cancer genes, but also novel candidate genes such as Mastermind-like1 (Mamld1) and Diacylglycerolkinase delta (Dgkd). We show that clonal expansion analysis by high-throughput sequencing is a robust approach for the identification of candidate cancer genes in insertional mutagenesis screens on the level of individual tumors. Solid tumors in mice were generated by somatic transposon mutagenesis with a PiggyBac transposon system. Insertion sites of transposons in 11 tumors and 6 non-cancerous tail controls were determined by Illumina high-throughput sequencing. Insertions were determined both on 5' and 3' sides of the transposon (PB5 and PB3, respectively). Quantitative analysis of read numbers revealed enrichment of certain insertions in tumors, but not in controls, and these enriched insertions identify candidate cancer genes.
Project description:Genomic DNA from pools of H. pylori strain G27 Clones as indicated (pools of 300 (300p) or insertions in specific mapped genes) were amplifed using the MATT method to label DNA adjacent to the site of transposon insertion with the primer pairs indicated. The left side of the transposon was labeled in the Cy3 channel (Primer S) and the right side of the transposon was labeled in the Cy5 channel (Primer N). The results of these experiments are published in Salama et al. 2004. J Bact. 186(23):7926-7935.
Project description:Somatic transposon mutagenesis in mice is an efficient strategy to investigate the genetic mechanisms of tumorigenesis. The identification of tumor driving transposon insertions traditionally requires the generation of large tumor cohorts to obtain information about common insertion sites. Tumor driving insertions are also characterized by their clonal expansion in tumor tissue, a phenomenon that is facilitated by the slow and evolving transformation process of transposon mutagenesis. We describe here an improved approach for the detection of tumor driving insertions that assesses the clonal expansion of insertions by quantifying the relative proportion of sequence reads obtained in individual tumors. To this end, we have developed a protocol for insertion site sequencing that utilizes acoustic shearing of tumor DNA and Illumina sequencing. We analyzed various solid tumors generated by PiggyBac mutagenesis and for each tumor >10^6 reads corresponding to >10^4 insertion sites were obtained. In each tumor, 9 to 25 insertions stood out by their enriched sequence read frequencies when compared to frequencies obtained from tail DNA controls. These enriched insertions are potential clonally expanded tumor driving insertions, and thus identify candidate cancer genes. The candidate cancer genes of our study comprised many established cancer genes, but also novel candidate genes such as Mastermind-like1 (Mamld1) and Diacylglycerolkinase delta (Dgkd). We show that clonal expansion analysis by high-throughput sequencing is a robust approach for the identification of candidate cancer genes in insertional mutagenesis screens on the level of individual tumors.
Project description:Transposons are genomic parasites, and their new insertions can cause instability and spur the evolution of their host genomes. Rapid accumulation of short-read whole-genome sequencing data provides a great opportunity for studying new transposon insertions and their impacts on the host genome. Although many algorithms are available for detecting transposon insertions, the task remains challenging and existing tools are not designed for identifying de novo insertions. Here, we present a new benchmark fly dataset based on PacBio long-read sequencing and a new method TEMP2 for detecting germline insertions and measuring de novo 'singleton' insertion frequencies in eukaryotic genomes. TEMP2 achieves high sensitivity and precision for detecting germline insertions when compared with existing tools using both simulated data in fly and experimental data in fly and human. Furthermore, TEMP2 can accurately assess the frequencies of de novo transposon insertions even with high levels of chimeric reads in simulated datasets; such chimeric reads often occur during the construction of short-read sequencing libraries. By applying TEMP2 to published data on hybrid dysgenic flies inflicted by de-repressed P-elements, we confirmed the continuous new insertions of P-elements in dysgenic offspring before they regain piRNAs for P-element repression. TEMP2 is freely available at Github: https://github.com/weng-lab/TEMP2.