Project description:We used H83M2 P element to ectopically expressed MSL2 protein in females to test if the novel formed MSL complex is the directly reason of dosage compensation Compare the MSL2 females with normal females and normal males; MSL2 males also included.
Project description:We used H83M2 P element to ectopically expressed MSL2 protein in females to test if the novel formed MSL complex is the directly reason of dosage compensation
Project description:The Drosophila male-specific lethal (MSL) complex binds to the male X chromosome to activate transcription, and consists of five proteins, MSL1, MSL2, MSL3, MOF, MLE, and two roX RNAs. The MLE helicase remodels the roX lncRNAs, enabling the lncRNA-mediated assembly of the Drosophila dosage compensation complex. MSL2 is expressed only in males and interacts with the N-terminal zinc-finger of the transcription factor CLAMP that is important for specific recruitment of the MSL complex on the male X chromosome. Here we found that the unstructured C-terminal region of MLE interacts with 6-7 zinc-finger domains of CLAMP. In vitro 4-5 zinc fingers are critical for specific DNA-binding of CLAMP with GA-repeats, which constitute the core motif at the high affinity binding sites for MSL proteins. Deletion of the Clamp Binding Domain (CBD) in MLE results in decreasing of MSL proteins association with male X chromosome and increasing of male lethality. These results suggest that interactions of unstructured regions in MSL2 and MLE with CLAMP zinc finger domains are important for the specific recruitment of the MSL complex on the male X chromosome.
Project description:Haploinsufficiency and aneuploidy are two phenomena, where alteration of gene dosage causes severe cellular defects ultimately resulting in developmental failures and disease. One remarkable exception is the X chromosome, where copy number differences between males and females are buffered through the action of dosage compensation systems. In Drosophila, the Male-Specific Lethal complex (MSLc) mediates two-fold upregulation of the single male X chromosome via Histone H4 lysine 16 acetylation (H4K16ac). The evolutionary origin and conservation of this process orchestrated by MSL2, the only male-specific protein within the fly MSLc, have remained unclear. Here, we report that MSL2, in addition to its function on the X, targets dosage-sensitive autosomal genes involved in patterning and morphogenesis. We show that the precise regulation of these genes by MSL2 is required for proper development of the fly wing. This set of dosage sensitive genes maintained such regulation during evolution, as MSL2 binds and similarly regulates mouse orthologues via deposition of H4K16ac. We propose that MSL2-mediated H4K16ac is an evolutionarily conserved process mediating gene-by-gene dosage compensation across flies and mammals.
Project description:Haploinsufficiency and aneuploidy are two phenomena, where alteration of gene dosage causes severe cellular defects ultimately resulting in developmental failures and disease. One remarkable exception is the X chromosome, where copy number differences between males and females are buffered through the action of dosage compensation systems. In Drosophila, the Male-Specific Lethal complex (MSLc) mediates two-fold upregulation of the single male X chromosome via Histone H4 lysine 16 acetylation (H4K16ac). The evolutionary origin and conservation of this process orchestrated by MSL2, the only male-specific protein within the fly MSLc, have remained unclear. Here, we report that MSL2, in addition to its function on the X, targets dosage-sensitive autosomal genes involved in patterning and morphogenesis. We show that the precise regulation of these genes by MSL2 is required for proper development of the fly wing. This set of dosage sensitive genes maintained such regulation during evolution, as MSL2 binds and similarly regulates mouse orthologues via deposition of H4K16ac. We propose that MSL2-mediated H4K16ac is an evolutionarily conserved process mediating gene-by-gene dosage compensation across flies and mammals.
Project description:The male-specific lethal dosage compensation complex (MSL complex or DCC), which consists of five proteins and two non-coding roX RNAs, is necessary for the transcriptional enhancement of X-linked genes to compensate for the sex chromosome monosomy in Drosophila XY males, compared with XX females. MSL2 is a single protein component of the DCC that is expressed only in males and is essential for the specific recruitment of the DCC to the high-affinity “entry” sites (HASs) on the X chromosome. MSL2, together with MSL1, forms the heterotetrameric DCC core. Here, we demonstrated that the N-terminal unstructured region of MSL1 interacts with many different DNA-binding proteins that contain clusters of the C2H2 zinc-finger domains. Amino acid deletions in the N-terminal region of MSL1 strongly affect the binding of the DCC to the HASs on the male X chromosome. However, the binding of MSL2 to autosomal promoters was unaffected by amino acid deletions in MSL1. Males expressing mutant variants of MSL1 died during the larvae stage, demonstrating the critical role played by the N-terminal region in DCC activity. Our results suggest that MSL1 interacts with a variety of DNA-binding proteins to increase the specificity of DCC recruitment to the male X chromosome.