Project description:In Drosophila, the global increase in transcription from the X chromosome in males to compensate for its monosomy is mediated by the male-specific-lethal complex (MSL-C) consisting of five proteins and two non-coding RNAs, roX1 and roX2. After an initial sequence dependent recognition by the MSL-C of 150-300 high affinity sites, the spreading to the majority of the X-linked genes depends on local MSL-C concentration and active transcription. Here we ask whether any additional RNA species are associated to the MSL-C. No additional roX were found but a strong association was found between the msl2 mRNA and the MSL-C. Based on our results we propose a model in which a non-chromatin associated partial or complete MSL-C titrates newly transcribed msl2 mRNA and thus feed-back regulates the amount of available MSL-C.
Project description:In Drosophila, the global increase in transcription from the X chromosome in males to compensate for its monosomy is mediated by the male-specific-lethal complex (MSL-C) consisting of five proteins and two non-coding RNAs, roX1 and roX2. After an initial sequence dependent recognition by the MSL-C of 150-300 high affinity sites, the spreading to the majority of the X-linked genes depends on local MSL-C concentration and active transcription. Here we ask whether any additional RNA species are associated to the MSL-C. No additional roX were found but a strong association was found between the msl2 mRNA and the MSL-C. Based on our results we propose a model in which a non-chromatin associated partial or complete MSL-C titrates newly transcribed msl2 mRNA and thus feed-back regulates the amount of available MSL-C. In total 12 samples; 4 Input files (4 different conditions) with the corresponding 8 RIP samples (2 different antibodies, same 4 conditions as Input)
Project description:In Drosophila, two chromosome-wide compensatory systems have been characterized; the dosage compensation system acting on the male X-chromosome and the chromosome specific regulation of genes located on the heterochromatic 4th chromosome. Dosage compensation in Drosophila is accomplished by hypertranscription of the single male X-chromosome mediated by the MSL-complex. The mechanism for this compensation is suggested to be an MSL-complex mediated enhanced transcriptional elongation while the mechanism for the compensation mediated by Painting of fourth (POF) on the 4th chromosome has remained elusive. Here we show that POF binds to nascent RNA and this binding is associated with an increase in amount of chromosome 4 transcripts. Furthermore, genes located on the 4th chromosome are enriched in binding of the nucleoplasmic nucleporin component NUP98 and this enrichment correlates to increased POF binding. We also show that genes located in heterochromatic regions have a shorter transition time from site of transcription and to the nuclear envelope. Our current work broadens the understanding about how genes in heterochromatic regions can overcome the repressive influence of their hostile environment.
Project description:MSL (Male-specific lethal) complex increases transcription on the single X chromosome of Drosophila males in order to equalize expression of X-linked genes between males (XY) and females (XX). The increase in transcript levels correlates with MSL- dependent acetylation of histone H4 at K16 within the bodies of active genes, but identification of the transcriptional step affected has not been possible. In this study, we use global run-on sequencing (GRO-seq) to examine the specific effect of MSL complex on RNA Polymerase II (RNAP II) on a genome-wide level. Results indicate that MSL complex enhances transcription by facilitating the progression of RNAP II across the bodies of active X-linked genes. Improving transcriptional output downstream of typical gene-specific control may explain how dosage compensation can be imposed on the diverse set of genes along an entire chromosome. Global Run-On Sequencing (GRO-Seq) reads, i.e., RNA-Seq of nascent RNA transcripts, from D. Melanogaster SL2 cells. Two biological replicates were analyzed.
Project description:In Drosophila, two chromosome-wide compensatory systems have been characterized; the dosage compensation system acting on the male X-chromosome and the chromosome specific regulation of genes located on the heterochromatic 4th chromosome. Dosage compensation in Drosophila is accomplished by hypertranscription of the single male X-chromosome mediated by the MSL-complex. The mechanism for this compensation is suggested to be an MSL-complex mediated enhanced transcriptional elongation while the mechanism for the compensation mediated by Painting of fourth (POF) on the 4th chromosome has remained elusive. Here we show that POF binds to nascent RNA and this binding is associated with an increase in amount of chromosome 4 transcripts. Furthermore, genes located on the 4th chromosome are enriched in binding of the nucleoplasmic nucleporin component NUP98 and this enrichment correlates to increased POF binding. We also show that genes located in heterochromatic regions have a shorter transition time from site of transcription and to the nuclear envelope. Our current work broadens the understanding about how genes in heterochromatic regions can overcome the repressive influence of their hostile environment. Pof mutant vs. wild type, 3 replicates