Trim33 binds and silences a class of young endogenous retroviruses in the mouse testis
Ontology highlight
ABSTRACT: Transposable elements (TEs) have been active in the mammalian genome for hundreds of millions of years and each TE has had a distinct period of transpositional activity, followed by inactivation. Mice carrying reporter transgenes can be used to model transcriptional silencing at TEs. A mutagenesis screen for modifiers of epigenetic gene silencing produced a line with a null mutation in Trim33. Heterozygous mutants displayed increased expression of the reporter transgene. ChIP-seq of Trim33 in testis revealed 9,109 peaks, mostly at promoters, across the mouse genome. Trim33 was enriched at many RLTR10B elements that are among the youngest retrotransposons in the mouse genome. RNA-seq revealed that testis of mice haploinsufficient for Trim33 had altered expression of a small group of genes. The gene with the most significant increase, Nmnat3, was found to be transcribed from an upstream RLTR10B element. We show that Trim33 is involved in repressing RLTR10B elements in mouse testis. Examination of Trim33 binding using ChIP sequencing and the result of Trim33 haploinsufficiency using RNA sequencing, in mouse testis
Project description:Transposable elements (TEs) have been active in the mammalian genome for hundreds of millions of years and each TE has had a distinct period of transpositional activity, followed by inactivation. Mice carrying reporter transgenes can be used to model transcriptional silencing at TEs. A mutagenesis screen for modifiers of epigenetic gene silencing produced a line with a null mutation in Trim33. Heterozygous mutants displayed increased expression of the reporter transgene. ChIP-seq of Trim33 in testis revealed 9,109 peaks, mostly at promoters, across the mouse genome. Trim33 was enriched at many RLTR10B elements that are among the youngest retrotransposons in the mouse genome. RNA-seq revealed that testis of mice haploinsufficient for Trim33 had altered expression of a small group of genes. The gene with the most significant increase, Nmnat3, was found to be transcribed from an upstream RLTR10B element. We show that Trim33 is involved in repressing RLTR10B elements in mouse testis.
Project description:PBDEs are widely used in consumer and household products as flame retardants. Many studies have shown that PBDEs could disrupt thyroid hormone homeostasis and adversely affect brain development. Here, we explored the toxical effects of BDE209 on HEK 293 cells and found that BDE209 may have a role in nucleosome remodeling. Many gene sets involved in cancer are enriched at the BDE209-treated sample. This indicates the carcinogenicity of BDE209. Interestingly, the impacts of BDE209 dissoved in DMSO on gene expression are more pronounced than the simple additive effects of BDE209 and DMSO alone. Gene expression profiles of human embryonic kidney 293 cells (HEK 293) cultured in normal medium, and medium containing BDE209 or DMSO were generated by deep sequencing, using Illumina HighSeq2000, respectively..
Project description:Small RNAs mediate gene silencing by binding Argonaute/Piwi proteins to regulate target RNAs. Here we describe small RNA profiling of the adult testes of Callithrix jacchus, the common marmoset. The most abundant class of small RNAs in the adult testis was piRNAs, while 353 novel miRNAs but few endo-siRNAs were also identified. MARWI, a marmoset homolog of mouse MIWI and a very abundant PIWI in adult testes, associates with piRNAs that show characteristics of mouse pachytene piRNAs. As in other mammals, most marmoset piRNAs are derived from conserved clustered regions in the genome, which are annotated as intergenic regions. However, some of these piRNA cluster regions contain antisense-orientated pseudogenes, suggesting regulation of parental functional protein-coding genes. More piRNAs map to transposable element (TE) subfamilies when they have copies in piRNA clusters. In addition, the strand-bias observed for piRNAs mapped to each TE subfamily correlates with the polarity of copies inserted in clusters. These findings suggest that pachytene piRNA clusters determine the abundance and strand-bias of TE-derived piRNAs, and also regulate protein-coding genes via pseudogene-derived piRNAs. small RNA levels in the adult marmoset testis, and MARWI-IP small RNA levels and RNA levels from the adult marmoset testis with two replicates.
Project description:Most mammalian transcription factors and cofactors occupy thousands of genomic sites and modulate the expression of large gene networks to implement their biological functions. In this study, we describe an exception to this paradigm. TRIM33 is identified here as a lineage dependency in B cell neoplasms and is shown to perform this essential function by associating with a single cis element. ChIP-seq analysis of TRIM33 in murine B cell leukemia revealed a preferential association with two lineage-specific enhancers that harbor an exceptional density of motifs recognized by the PU.1 transcription factor. TRIM33 is recruited to these elements by PU.1, yet acts to antagonize PU.1 function. One of the PU.1/TRIM33 co-occupied enhancers is upstream of the pro-apoptotic gene Bim, and deleting this enhancer renders TRIM33 dispensable for leukemia cell survival. These findings reveal an essential role for TRIM33 in preventing apoptosis in B lymphoblastic leukemia by interfering with enhancer-mediated Bim activation. ChIP-Seq for Trim33, Pu.1 and histone modification marks in different types of leukemia cells
Project description:Understanding the extent of genomic transcription and its functional relevance is a central goal in genomics research. However, detailed genome‐wide investigations of transcriptome complexities in major mammalian organs and their underlying cellular sources, transcriptional mechanisms, and functional relevance have been scarce. Here we first show, using extensive RNA‐seq data, that transcription of both functional and nonfunctional genomic elements is substantially more widespread in the testis than in other organs across representative mammals. By scrutinizing the transcriptomes of all main testicular cell types in the mouse, we then reveal that meiotic spermatocytes and especially post‐meiotic round spermatids have remarkably diverse transcriptomes, which explains the high transcriptome complexity of the testis as a whole. The widespread transcriptional activity in spermatocytes and spermatids encompasses protein‐coding genes and long noncoding RNA genes but also poorly conserved intergenic sequences, suggesting that much of it is not of immediate functional relevance. Rather, our analyses of genome‐wide epigenetic data show that this prevalent transcription, which apparently promoted the birth of new genes during evolution, results from a highly permissive chromatin state during and after meiosis that may ultimately facilitate the replacement of histones by protamines during late spermatogenesis. To study the cellular source and mechanisms of high transcriptome complexity in the mammalian testis, we generated strand-specific deep coverage RNA‐Seq data for purified sertoli cells, spermatogonia, spermatocytes, spermatids and spermatozoa as well as for brain, liver and the whole testis from the mouse. We prepared 8 sequencing libraries for the polyadenylated RNA fraction of each sample and sequenced each library in 3 lanes of the Illumina Genome Analyser IIx platform, yielding a total of >60 millions strand-specific reads of 76 base pairs per sample. In addition, we generated ChIP-Seq data for the H3K4me2 modification as well as RRBS data for brain, liver, testis, spermatocytes and spermatids. RNA-seq, ChIP-seq and RRBS data were generated from the same individual or pool of individuals, in the case of purified cells. RNA-Seq of brain, liver and the whole testis
Project description:In mammals, sex determination depends on the paternal transmission of the Y chromosome, which bears the Sry gene. At the time of sex determination, Sry becomes up-regulated in XY gonads initiating the expression of various factors required for testicular development. Most of these factors remain to be identified. As a consequence, the genetic causes of gonadal dysgenesis in human patients, other than those involving SRY, remain unknown. We found that Nrg1 is a new gene involved in early testicular development. To study the role of Nrg1 in embryonic testicular differentiation, conditional inactivation of Nrg1 was achieved with the help of a Wt1-Cre line. Mutant mice show defects of testis development. In order to correlate the defects of cellular processes and the misregulated gene network(s), expression profiles were examined in controls and mutants testes at 13.5 dpc. Each testis sample was pooled from eight embryos.
Project description:Understanding the extent of genomic transcription and its functional relevance is a central goal in genomics research. However, detailed genomewide investigations of transcriptome complexities in major mammalian organs and their underlying cellular sources, transcriptional mechanisms, and functional relevance have been scarce. Here we first show, using extensive RNAseq data, that transcription of both functional and nonfunctional genomic elements is substantially more widespread in the testis than in other organs across representative mammals. By scrutinizing the transcriptomes of all main testicular cell types in the mouse, we then reveal that meiotic spermatocytes and especially postmeiotic round spermatids have remarkably diverse transcriptomes, which explains the high transcriptome complexity of the testis as a whole. The widespread transcriptional activity in spermatocytes and spermatids encompasses protein coding genes and long noncoding RNA genes but also poorly conserved intergenic sequences, suggesting that much of it is not of immediate functional relevance. Rather, our analyses of genomewide epigenetic data show that this prevalent transcription, which apparently promoted the birth of new genes during evolution, results from a highly permissive chromatin state during and after meiosis that may ultimately facilitate the replacement of histones by protamines during late spermatogenesis. To study the cellular source and mechanisms of high transcriptome complexity in the mammalian testis, we generated strand-specific deep coverage RNASeq data for purified sertoli cells, spermatogonia, spermatocytes, spermatids and spermatozoa as well as for brain, liver and the whole testis from the mouse. We prepared 8 sequencing libraries for the polyadenylated RNA fraction of each sample and sequenced each library in 3 lanes of the Illumina Genome Analyser IIx platform, yielding a total of >60 millions strand-specific reads of 76 base pairs per sample. In addition, we generated ChIP-Seq data for the H3K4me2 modification as well as RRBS data for brain, liver, testis, spermatocytes and spermatids. RNA-seq, ChIP-seq and RRBS data were generated from the same individual or pool of individuals, in the case of purified cells. RNASeq data for purified sertoli cells, spermatogonia, spermatocytes, spermatids and spermatozoa
Project description:Taf7l (a paralogue of Taf7) and Trf2 (a TBP-related protein) are components of the core promoter complex required for gene/tissue-specific transcription of protein-coding genes by RNA polymerase II. Previous studies reported that Taf7l knockout mice exhibit structurally abnormal sperm, reduced sperm count, weakened motility and compromised fertility. Here we find that continued backcrossing of Taf7l-/Y mice from N5 to N9 produced KO males that are essentially sterile. Genome-wide expression profiling by mRNA-seq analysis of wild type (WT) and Taf7l-/Y (KO) testes revealed that Taf7l ablation impairs the expression of many post-meiotic spermatogenic specific as well as metabolic genes. Importantly, histological analysis of testes revealed that Taf7l-/Y mice develop post-meiotic arrest at the first stage of spermiogenesis, phenotypically similar to Trf2-/- mice, but distinct from Taf4b-/- mice. Indeed, we find that Taf7l and Trf2 co-regulate post-meiotic genes, but none of Taf4b-regulated germ stem cell genes in testes. Genome-wide ChIP-seq studies indicate that TAF7L binds to promoters of activated post-meiotic genes in testis. Moreover, biochemical studies show that TAF7L associates with TRF2 both in vitro and in testis suggesting that TAF7L likely cooperates directly with TRF2 at promoters of a subset of post-meiotic genes to regulate spermiogenesis. Our findings thus provide a new mechanism for cell-type specific transcriptional control involving an interaction between a ‘non-prototypic’ core promoter recognition factor (Trf2) and an orphan TAF subunit (Taf7l) in mammalian testis-specific gene transcription. Genome-wide mapping of TAF7L and Pol II in testis tissue, and mRNA-seq expression profiling wild type and Taf7l knockout testis.
Project description:We study the changes occurring in the testes of Talpa occidentalis during the breeding cycle. The transcriptomic analysis of active, inactivating and regressed testis show that several molecular pathways that operate in Sertoli cells, involved in the control of spermatogenesis and BTB dynamics, are deregulated in the inactive gonad, and that the immuno privilege of the testes is lost during the non-breeding season.