Project description:Sexual dimorphism depends on sex-biased gene expression, but the contributions of microRNAs (miRNAs) have not been globally assessed. We therefore produced an extensive small RNA sequencing dataset to analyse male and female miRNA expression profiles in mouse, opossum and chicken. Our analyses uncovered numerous cases of somatic sex-biased miRNA expression, especially in the mouse heart and liver. Sex-biased expression is explained by miRNA-specific regulation, including sex-biased chromatin accessibility at promoters, rather than piggybacking of intronic miRNAs on sex-biased protein-coding genes. In mouse, but not opossum and chicken, sex bias is coordinated across tissues such that autosomal testis-biased miRNAs tend to be somatically male-biased, whereas autosomal ovary-biased miRNAs are female-biased, possibly due to broad hormonal control. In chicken, which has a Z/W sex chromosome system, expression output of genes on the Z chromosome is expected to be male-biased, since there is no global dosage compensation mechanism that restores expression in ZW females after almost all genes on the W chromosome decayed. Nevertheless, we found that the dominant liver miRNA, miR-122-5p, is Z-linked but expressed in an unbiased manner, due to the unusual retention of a W-linked copy. Another Z-linked miRNA, the male-biased miR-2954-3p, shows conserved preference for dosage-sensitive genes on the Z chromosome, based on computational and experimental data from chicken and zebra finch, and acts to equalise male-to-female expression ratios of its targets. Unexpectedly, our findings thus establish miRNA regulation as a novel gene-specific dosage compensation mechanism.
Project description:Relative expression levels of mRNAs in chicken cecal epithelia experimentally infected with Eimeria tenella were measured at 4.5 days post-infection. Two weeks old chickens were uninfected (negative control) or were orally inoculated with sporulated oocysts of Eimeria tenella. Cecal epithelia samples were collected from >12 birds in infected or uninfected group at 4.5 d following infections, in which samples from 4 birds were pooled together to form a total 3 biological replicates in each group. Parasite merozoites were also collected from four infected chickens at 5 d after infections. Uninfected control samples, merozoites and infection group samples were selected for RNA extraction and hybridization on Affymetrix microarrays. We used Affymetrix GeneChip chicken genome arrays to detail the chicken cecal epithelia gene expression in the control and E. tenella-infected birds.
Project description:Relative expression levels of mRNAs in chicken cecal epithelia experimentally infected with Eimeria tenella were measured at 4.5 days post-infection. Two weeks old chickens were uninfected (negative control) or were orally inoculated with sporulated oocysts of Eimeria tenella. Cecal epithelia samples were collected from >12 birds in infected or uninfected group at 4.5 d following infections, in which samples from 4 birds were pooled together to form a total 3 biological replicates in each group. Parasite merozoites were also collected from four infected chickens at 5 d after infections. Uninfected control samples, merozoites and infection group samples were selected for RNA extraction and hybridization on Affymetrix microarrays. We used Affymetrix GeneChip chicken genome arrays to detail the chicken cecal epithelia gene expression in the control and E. tenella-infected birds. Infected, uninfected chicken cecal epithelia and merozoites were selected for RNA extraction and hybridization with Affymetrix microarrays. Our goal was to analyze global transcriptome changes in chicken cecal mucous membranes in response to E. tenella infection in vivo. We used infected (T1,T2,T3; three biological replicates) and uninfected (Neg1, Neg2, Neg3; three biological replicates) samples to identify genes that were differentially expressed. Meanwhile, RNA and probes were also prepared from parasite merozoites (Mzt) from infected samples (Mzt) and used as an additional control in microarray hybridization.
Project description:Purpose: Accurate identification of sex-biased genes requires precise measurement of gene expression levels in gonads. This study is designed to provide such data for various Drosophila species to enhance studies of sex-biased gene expression and evolution across the genus. Methods: Virgin flies were collected and aged 6-10 days before dissecting 2-3 replicates of testes or ovaries. Total RNA was extracted using the Arcturus® PicoPure® kit . Illumina® TruSeq® RNA library kits were used to poly-A+ select and reverse-transcribe mRNA, shear cDNA into ~120 bp fragments, and produce libraries for 1x50 bp sequencing on an Illumina GAIIx or HiSeq2000. Illumina®’s Real Time Analysis v1.13 module processed images, called bases, and provided base qualities. Reads were mapped to the current reference genomes using Bowtie v2.1.0 (Langmead and Salzberg, 2012, Nat Meth) with default settings. Differentially expressed genes were detected using Cufflinks v 2.1.0 (Trapnell et al., 2010, Nat Biotech; default settings) or edgeR (Robinson et al., 2010, Bioinformatics; full-quantile GC-content normalization and full-quantile between-sample normalization). Genes were called differentially expressed at a Benjamini-Hochberg false discovery rate of 0.01. Results: Thousands of male- and female-biased genes were detected for each species using both DE detection methods. These results provide a significant improvement in sensitivity of sex-biased gene detection relative to using whole-body RNA-sequencing data. These data provide a foundation for accurate identification of sex-biased genes throughout the Drosophila genus. Testis and ovary samples from Drosophila species were sequenced 1 x 50 bp in duplicate from 6-10 day old virgin, Wolbachia-free adult flies on an Illumina GAIIx or HiSeq2000.
Project description:Sex chromosomes are characterized by a non-random content of genes with preferential expression in one sex. The mechanisms which are responsible for this phenomenon are, however, largely unresolved. To elucidate selective forces shaping the Z chromosome gene content in chicken, we analyzed microarray data from adult and embryonic gonads (the latter already available in GEO Series GSE8693). Experiment Overall Design: Total RNA from gonads of 8 males and 8 females was used for hybridization to Affymetrix GeneChip® Chicken Genome Arrays. Prior to hybridization the samples were combined in equal quantities into 4 pools (4 testes/ovary samples in each pool), 2 of them representing testis and 2 ovary. Experiment Overall Design: All four GeneChips met Affymetrix quality control criteria. Furthermore, all chips were checked by methods based on probe level robust linear model fitting provided by "affyPLM" package (Bolstad, 2007). None of the chips showed any signs of abnormality.
Project description:Expression of known and predicted genes in tissues of Gallus gallus (chicken) pooled from multiple healthy individuals. Two-colour experiments with two different tissues hybridized to each array. Each tissue is arrayed in replicate with dye swaps. Tissues: Bursa of Fabricius, Cerebellum, Cerebral cortex, Eye, Femur with bone marrow, Gallbladder, Gizzard, Heart, Intestine, Kidney, Liver, Lung, Muscle, Ovary, Oviduct, Skin, Spleen, Stomach, Testis, Thymus