| 1. |
- Bonke, M, et al.
(författare)
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Transcriptional networks controlling the cell cycle
- 2013
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Ingår i: G3 (Bethesda, Md.). - : Oxford University Press (OUP). - 2160-1836. ; 3:1, s. 75-90
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we map the transcriptional targets of 107 previously identified Drosophila genes whose loss caused the strongest cell-cycle phenotypes in a genome-wide RNA interference screen and mine the resulting data computationally. Besides confirming existing knowledge, the analysis revealed several regulatory systems, among which were two highly-specific and interconnected feedback circuits, one between the ribosome and the proteasome that controls overall protein homeostasis, and the other between the ribosome and Myc/Max that regulates the protein synthesis capacity of cells. We also identified a set of genes that alter the timing of mitosis without affecting gene expression, indicating that the cyclic transcriptional program that produces the components required for cell division can be partially uncoupled from the cell division process itself. These genes all have a function in a pathway that regulates the phosphorylation state of Cdk1. We provide evidence showing that this pathway is involved in regulation of cell size, indicating that a Cdk1-regulated cell size checkpoint exists in metazoans.
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| 2. |
- Crooks, Lucy, et al.
(författare)
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Identification of Null Alleles and Deletions from SNP Genotypes for an Intercross Between Domestic and Wild Chickens
- 2013
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Ingår i: G3. - : Oxford University Press (OUP). - 2160-1836. ; 3:8, s. 1253-1260
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed genotypes from similar to 10K single-nucleotide polymorphisms (SNPs) in two families of an F-2 intercross between Red Junglefowl and White Leghorn chickens. Possible null alleles were found by patterns of incompatible and missing genotypes. We estimated that 2.6% of SNPs had null alleles compared with 2.3% with genotyping errors and that 40% of SNPs in which a parent and offspring were genotyped as different homozygotes had null alleles. Putative deletions were identified by null alleles at adjacent markers. We found two candidate deletions that were supported by fluorescence intensity data from a 60K SNP chip. One of the candidate deletions was from the Red Junglefowl, and one was present in both the Red Junglefowl and White Leghorn. Both candidate deletions spanned protein-coding regions and were close to a previously detected quantitative trait locus affecting body weight in this population. This study demonstrates that the similar to 50K SNP genotyping arrays now available for several agricultural species can be used to identify null alleles and deletions in data from large families. We suggest that our approach could be a useful complement to linkage analysis in experimental crosses.
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| 3. |
- Jewett, M. C., et al.
(författare)
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Mapping Condition-Dependent Regulation of Lipid Metabolism in Saccharomyces cerevisiae
- 2013
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Ingår i: G3: Genes, Genomes, Genetics. - : Oxford University Press (OUP). - 2160-1836. ; 3:11, s. 1979-1995
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Tidskriftsartikel (refereegranskat)abstract
- Lipids play a central role in cellular function as constituents of membranes, as signaling molecules, and as storage materials. Although much is known about the role of lipids in regulating specific steps of metabolism, comprehensive studies integrating genome-wide expression data, metabolite levels, and lipid levels are currently lacking. Here, we map condition-dependent regulation controlling lipid metabolism in Saccharomyces cerevisiae by measuring 5636 mRNAs, 50 metabolites, 97 lipids, and 57 C-13-reaction fluxes in yeast using a three-factor full-factorial design. Correlation analysis across eight environmental conditions revealed 2279 gene expression level-metabolite/lipid relationships that characterize the extent of transcriptional regulation in lipid metabolism relative to major metabolic hubs within the cell. To query this network, we developed integrative methods for correlation of multi-omics datasets that elucidate global regulatory signatures. Our data highlight many characterized regulators of lipid metabolism and reveal that sterols are regulated more at the transcriptional level than are amino acids. Beyond providing insights into the systems-level organization of lipid metabolism, we anticipate that our dataset and approach can join an emerging number of studies to be widely used for interrogating cellular systems through the combination of mathematical modeling and experimental biology.
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| 4. |
- Larsson, Hanna, et al.
(författare)
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Distribution of Long-Range Linkage Disequilibrium and Tajima's D Values in Scandinavian Populations of Norway Spruce (Picea abies)
- 2013
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Ingår i: G3. - : Oxford University Press (OUP). - 2160-1836. ; 3:5, s. 795-806
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Tidskriftsartikel (refereegranskat)abstract
- The site frequency spectrum of mutations (SFS) and linkage disequilibrium (LD) are the two major sources of information in population genetics studies. In this study we focus on the levels of LD and the SFS and on the effect of sample size on summary statistics in 10 Scandinavian populations of Norway spruce. We found that previous estimates of a low level of LD were highly influenced by both sampling strategy and the fact that data from multiple loci were analyzed jointly. Estimates of LD were in fact heterogeneous across loci and increased within individual populations compared with the estimate from the total data. The variation in levels of LD among populations most likely reflects different demographic histories, although we were unable to detect population structure by using standard approaches. As in previous studies, we also found that the SFS-based test Tajima's D was highly sensitive to sample size, revealing that care should be taken to draw strong conclusions from this test when sample size is small. In conclusion, the results from this study are in line with recent studies in other conifers that have revealed a more complex and variable pattern of LD than earlier studies suggested and with studies in trees and humans that suggest that Tajima's D is sensitive to sample size. This has large consequences for the design of future association and population genetic studies in Norway spruce.
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| 5. |
- Lundberg, Lina E, 1982-, et al.
(författare)
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Targeting of painting of fourth to roX1 and roX2 proximal sites suggests evolutionary links between dosage compensation and the regulation of the 4th chromosome in Drosophila melanogaster
- 2013
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Ingår i: G3. - : Oxford University Press (OUP). - 2160-1836. ; 3:8, s. 1325-1334
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Tidskriftsartikel (refereegranskat)abstract
- In Drosophila melanogaster, two chromosome-specific targeting and regulatory systems have been described. The male-specific lethal (MSL) complex supports dosage compensation by stimulating gene expression from the male X-chromosome and the protein Painting of fourth (POF) specifically targets and stimulates expression from the heterochromatic 4(th) chromosome. The targeting sites of both systems are well characterized, but the principles underlying the targeting mechanisms have remained elusive. Here we present an original observation, namely that POF specifically targets two loci on the X-chromosome, PoX1 and PoX2 (POF-on-X). PoX1 and PoX2 are located close to the roX1 and roX2 genes, which encode ncRNAs important for the correct targeting and spreading of the MSL-complex. We also found that the targeting of POF to PoX1 and PoX2 is largely dependent on roX expression and identified a high-affinity target region which ectopically recruits POF. The results presented support a model linking the MSL-complex to POF and dosage compensation to regulation of heterochromatin.
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| 6. |
- Moumad, Khalid, et al.
(författare)
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Genetic Polymorphisms in Host Innate Immune Sensor Genes and the Risk of Nasopharyngeal Carcinoma in North Africa
- 2013
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Ingår i: G3: Genes, Genomes, Genetics. - : Oxford University Press (OUP). - 2160-1836. ; 3:6, s. 971-977
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Tidskriftsartikel (refereegranskat)abstract
- Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world. It is an Epstein-Barr virus-associated malignancy with an unusual racial and geographical distribution. The host innate immune sensor genes play an important role in infection recognition and immune response against viruses. Therefore, we examined the association between polymorphisms in genes within a group of pattern recognition receptors (including families of Toll-like receptors, C-type lectin receptors, and retinoic acid-inducible gene I-like receptors) and NPC susceptibility. Twenty-six single-nucleotide polymorphisms (SNPs) in five pattern-recognition genes were genotyped in 492 North African NPC cases and 373 frequency-matched controls. TLR3_rs3775291 was the most significantly associated SNP (odds ratio [OR] 1.49; 95% confidence interval [95% CI] 1.11-2.00; P = 0.008; dominant model). The analysis showed also that CD209_rs7248637 (OR 0.69; 95% CI 0.52-0.93; P = 0.02; dominant model) and DDX58_rs56309110 (OR 0.70; 95% CI 0.51-0.98; P = 0.04) were associated with the risk of NPC. An 18% increased risk per allele was observed for the five most significantly associated SNPs, TLR3_rs3775291, CD209_rs7248637, DDX58_rs56309110, CD209_rs4804800, and MBL2_rs10824792, (p(trend) = 8.2 x 10(-4)). Our results suggest that genetic variation in pattern-recognition genes is associated with the risk of NPC. These preliminary findings require replication in larger studies.
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| 7. |
- Nelson, Ronald, et al.
(författare)
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MAPfastR : Quantitative trait loci mapping in outbred line crosses
- 2013
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Ingår i: G3. - : Oxford University Press (OUP). - 2160-1836. ; 3, s. 2147-2149
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Tidskriftsartikel (refereegranskat)abstract
- MAPfastR is a software package developed to analyze quantitative trait loci data from inbred and outbred line-crosses. The package includes a number of modules for fast and accurate quantitative trait loci analyses. It has been developed in the R language for fast and comprehensive analyses of large datasets. MAPfastR is freely available at: http://www.computationalgenetics.se/?page_id=7
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| 8. |
- Pettersson, Mats, et al.
(författare)
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Dynamics of adaptive alleles in divergently selected body weight lines of chickens.
- 2013
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Ingår i: G3. - : Oxford University Press (OUP). - 2160-1836. ; 3:12
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Tidskriftsartikel (refereegranskat)abstract
- By studying genomic changes over time in populations subjected to strong artificial directional selection, we can gain insights to the dynamics of beneficial alleles originating from the founder population or emerging as novel mutations undergoing ongoing selection. The Virginia lines are a chicken resource population generated by long-term bi-directional, single-trait selection for juvenile body weight. We studied genome-wide allele frequency changes from generation 40 to 53 using genome-wide genotypes from directional and relaxed selection lines. Overall, there were small changes in allele frequencies at individual loci over the studied time period; but, on average, the changes were greater in lines with larger phenotypic changes. This is consistent with previous findings that much of the response to selection over the first 40 years of selection was attributable to utilization of standing genetic variation at many loci in the genome, indicating a mostly polygenic architecture for body weight. Over the course of the selection experiment, the largest phenotypic response to selection was observed in the high-weight selected line, and in this line we detected a single locus where the allele frequency changed rapidly during a late stage of the experiment. This locus likely contains a novel, beneficial mutation that appeared between generations 40 and 45 and was driven to fixation in 5 to 10 generations. This result illustrates the dependence of continued long-term selection response on standing genetic variation at many loci as well as strong, novel, beneficial mutations.
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