Unknown,Transcriptomics,Genomics,Proteomics

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Transcription profiling of Drosophila msl21 male larvae reveals MSL2 is required for upregulation of male X chromosome but not for expression of autosomal genes

ABSTRACT: Drosophila males double transcription of their single X chromosome to equalize X-linked gene expression with females, which carry two X chromosomes. Increased transcription requires the Male-Specific Lethal (MSL) complex. The MSL2 protein is essential component of the MSL complex. MSL2 is the only protein that is strictly limited to males. MSL2 together with MSL1 forms the core of the MSL complex. The global effect of msl2 mutation on gene expression was measured by microarray analysis. We found that expression of the X chromosome was decreased in msl21 male larvae, supporting the involvement of MSL2 in the up-regulation of X-linked genes. However, there was no change in expression of 4th chromosomal and heterochromatic genes. This finding is broadly comparable to reports of reduced X chromosome expression following msl2 RNAi knockdown in S2 cells. Hence MSL2 is required for up-regulation of male X chromosome where as it is not necessary for normal expression of 4th chromosomal genes and heterochromatic genes in Drosophila melanogaster males. Experiment Overall Design: Total RNA was prepared from groups of 50 (or more in case of smaller larvae) third instar larvae by TRIzol (Invitrogen) extraction and purified using the RNeasy kit (Qiagen). Three independent RNA preparations for each genotype served as templates for probe synthesis. Affymetrix Drosophila Genome 2.0 chips were hybridized to these probes (Santa Clara, CA). Affymetrix Gene expression data was background corrected, normalized and summarized into a one expression value per sample and probeset using the RMA (robust multi-array average) algorithm. Changes in gene expression (log2 fold changes) were determined by comparing the mean RMA expression values in the msl21 sample to the mean RMA expression values in the msl21/+ samples.

ORGANISM(S): Drosophila melanogaster

SUBMITTER: Satya Kiran Koya

PROVIDER: E-GEOD-12054 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Coordinated regulation of heterochromatic genes in Drosophila melanogaster males.

Deng Xinxian X Koya S Kiran SK Kong Ying Y Meller Victoria H VH

Genetics 20090323 2

Dosage compensation modifies the chromatin of X-linked genes to assure equivalent expression in sexes with unequal X chromosome dosage. In Drosophila dosage compensation is achieved by increasing expression from the male X chromosome. The ribonucleoprotein dosage compensation complex (DCC) binds hundreds of sites along the X chromosome and modifies chromatin to facilitate transcription. Loss of roX RNA, an essential component of the DCC, reduces expression from X-linked genes. Surprisingly, loss ...[more]

PMID: 19307603

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Project description:roX RNAs are involved in the chromosome-wide gene regulation that occurs during dosage compensation in Drosophila. Dosage compensation equalizes expression of X-linked and autosomal genes. Drosophila males increase transcription two-fold from their single X chromosome. This is mediated by the MSL complex, which is composed of the male-specific lethal (MSL) proteins and two noncoding roX RNAs, roX1 and roX2. Upon elimination of both roX transcripts, a global decrease of X-linked gene expression is observed in males. Expression of the genes on the entire 4th chromosome also decreased in the absence of both roX transcripts. roX1 RNA also presents in females in the early stages. To investigate the effect of loss of roX transcripts on gene expression in females, gene expression was analyzed by microarrays in roX1-roX2- female flies. To eliminate inconsistency caused by differences in genetic background, expression of roX1-roX2- females with females of virtually identical genetic background but carrying the [hsp83-roX1+] transgene were compared. Expression of any chromosome did not change in roX1-roX2- females. It was concluded that roX RNAs only effect in males . Experiment Overall Design: Total RNA was prepared from groups of 50 third instar larvae by TRIzol (Invitrogen) extraction and purified using the RNeasy kit (Qiagen). Three independent RNA preparations for each genotype served as templates for probe synthesis. These probes were hybridized to Affymetrix Drosophila Genome 2.0 chips (Santa Clara, CA). Genes were filtered for present/absent calls by a PM-MM (Perfect match-Mismatch) comparison. Affymetrix Gene expression data was background corrected, normalized and summarized into a one expression value per replicate sample and probeset using the RMA (robust multi-array average) algorithm. Changes in gene expression were determined by comparing the mean signal intensities of genes on arrays hybridized with roX1- roX2- (mutant) probes to those hybridized with roX1- roX2-; [hsp83-roX1+] (control) probes.

Dataset Information

Transcription profiling of Drosophila msl21 male larvae reveals MSL2 is required for upregulation of male X chromosome but not for expression of autosomal genes

Publications

Coordinated regulation of heterochromatic genes in Drosophila melanogaster males.

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