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Pervasive and largely lineage-specific adaptive protein evolution in the dosage compensation complex of Drosophila melanogaster.

ABSTRACT: Dosage compensation refers to the equalization of X-linked gene transcription among heterogametic and homogametic sexes. In Drosophila, the dosage compensation complex (DCC) mediates the twofold hypertranscription of the single male X chromosome. Loss-of-function mutations at any DCC protein-coding gene are male lethal. Here we report a population genetic analysis suggesting that four of the five core DCC proteins--MSL1, MSL2, MSL3, and MOF--are evolving under positive selection in D. melanogaster. Within these four proteins, several domains that range in function from X chromosome localization to protein-protein interactions have elevated, D. melanogaster-specific, amino acid divergence.

SUBMITTER: Levine MT

PROVIDER: S-EPMC2147993 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature

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Pervasive and largely lineage-specific adaptive protein evolution in the dosage compensation complex of Drosophila melanogaster.

Levine Mia T MT Holloway Alisha K AK Arshad Umbreen U Begun David J DJ

Genetics 20071101 3

Dosage compensation refers to the equalization of X-linked gene transcription among heterogametic and homogametic sexes. In Drosophila, the dosage compensation complex (DCC) mediates the twofold hypertranscription of the single male X chromosome. Loss-of-function mutations at any DCC protein-coding gene are male lethal. Here we report a population genetic analysis suggesting that four of the five core DCC proteins--MSL1, MSL2, MSL3, and MOF--are evolving under positive selection in D. melanogast ...[more]

PMID: 18039888

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Male-Killing Spiroplasma Alters Behavior of the Dosage Compensation Complex during Drosophila melanogaster Embryogenesis.

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Rapid Evolution of Autosomal Binding Sites of the Dosage Compensation Complex in <i>Drosophila melanogaster</i> and Its Association With Transcription Divergence.

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Satellite Repeats Identify X Chromatin for Dosage Compensation in Drosophila melanogaster Males.

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An evolutionary consequence of dosage compensation on Drosophila melanogaster female X-chromatin structure?

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| S-EPMC2820458 | biostudies-literature

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RNA-on-X 1 and 2 in Drosophila melanogaster fulfill separate functions in dosage compensation.

Project description:In Drosophila melanogaster, the male-specific lethal (MSL) complex plays a key role in dosage compensation by stimulating expression of male X-chromosome genes. It consists of MSL proteins and two long noncoding RNAs, roX1 and roX2, that are required for spreading of the complex on the chromosome and are redundant in the sense that loss of either does not affect male viability. However, despite rapid evolution, both roX species are present in diverse Drosophilidae species, raising doubts about their full functional redundancy. Thus, we have investigated consequences of deleting roX1 and/or roX2 to probe their specific roles and redundancies in D. melanogaster. We have created a new mutant allele of roX2 and show that roX1 and roX2 have partly separable functions in dosage compensation. In larvae, roX1 is the most abundant variant and the only variant present in the MSL complex when the complex is transmitted (physically associated with the X-chromosome) in mitosis. Loss of roX1 results in reduced expression of the genes on the X-chromosome, while loss of roX2 leads to MSL-independent upregulation of genes with male-biased testis-specific transcription. In roX1 roX2 mutant, gene expression is strongly reduced in a manner that is not related to proximity to high-affinity sites. Our results suggest that high tolerance of mis-expression of the X-chromosome has evolved. We propose that this may be a common property of sex-chromosomes, that dosage compensation is a stochastic process and its precision for each individual gene is regulated by the density of high-affinity sites in the locus.

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The chromosomal high-affinity binding sites for the Drosophila dosage compensation complex.

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| S-EPMC2586088 | biostudies-literature

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