Project description:To study the influence of POF on transcription in testis we made expression arrays from dissected testes (Pof mutants and wild type control). It is clear that POF mainly alters the expression of genes on the fourth chromosome Keywords: mutant analysis
Project description: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 4th 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.
Project description:To study the influence of POF on transcription in testis we made expression arrays from dissected testes (Pof mutants and wild type control). It is clear that POF mainly alters the expression of genes on the fourth chromosome Experiment Overall Design: Three replicates, each of 60 testes from 0-24h old males (Pof mutants and wild type control), were dissected and total RNA prepared
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
Project description:Analysis of expression in pof mutant and wt 1st instar larvae Experiment Overall Design: 400 1st instar larvae were used for each of 4 biological replicates of pof mutants and 3 replicates of wt larvae.