Dosage compensation

About: Dosage compensation is a research topic. Over the lifetime, 1920 publications have been published within this topic receiving 124589 citations.

Combined effects of dosage compensation and incomplete dominance on gene expression in triploid cyprinids

Abstract: Hybridization and polyploidy are pervasive evolutionary features of flowering plants and frequent among some animal groups, such as fish. These processes always lead to novel genotypes and various phenotypes, including growth heterosis. However, its genetic basis in lower vertebrate is still poorly understood. Here, we conducted transcriptome-level analyses of the allopolyploid complex of Carassius auratus red var. (R) (♀) × Cyprinus carpio L. (C) (♂), including the allodiploid and allotetraploid with symmetric subgenomes, and the two allotriploids with asymmetric subgenomes. The gradual changes of gene silencing and novel gene expression suggested the weakening of the constraint of polymorphic expression in genotypic changes. Then, analyses of the direction and magnitude of homoeolog expression exhibited various asymmetric expression patterns, which supported that R incomplete dominance and dosage compensation were co-regulated in the two triploids. Under these effects, various magnitudes of R-homoeolog expression bias were observed in growth-regulated genes, suggesting that they might contribute to growth heterosis in the two triploids. The determination of R incomplete dominance and dosage compensation, which might be led by asymmetric subgenomes and multiple sets of homologous chromosomes, explained why various expression patterns were shaped and their potential contribution to growth heterosis in the two triploids.

Proximity ligation assays of protein and RNA interactions in the male-specific lethal complex on Drosophila melanogaster polytene chromosomes

Abstract: In Drosophila, the male-specific lethal (MSL) complex specifically targets the male X chromosome and participates in a twofold increase in expression output leading to functional dosage compensation. The complex includes five proteins and two non-coding RNAs (ncRNAs). A number of additional associated factors have also been identified. However, the components' roles and interactions have not been fully elucidated. The in situ proximity ligation assay (PLA) provides a sensitive means to determine whether proteins and other factors have bound to chromosomes in close proximity to each other, and thus may interact. Thus, we modified, tested, and applied the assay to probe interactions of MSL complex components on polytene chromosomes. We show that in situ PLA can detect and map both protein-protein and protein-ncRNA interactions on polytene chromosomes at high resolution. We further show that all five protein components of the MSL complex are in close proximity to each other, and the ncRNAs roX1 and roX2 bind the complex in close proximity to MLE. Our results also indicate that JIL1, a histone H3 Ser10 kinase enriched on the male X chromosome, interacts with MSL1 and MSL2, but not MSL3 of the MSL complex. In addition, we corroborate proposed interactions of the MSL complex with both CLAMP and TopoII.

A robust and powerful test for case-control genetic association study on X chromosome.

Abstract: Hundreds of genome-wide association studies were conducted to map the disease genes on autosomes in human beings It is known that many complex diseases are sex-determined and X chromosome is expected to play an important role However, only a few single-nucleotide polymorphisms on X chromosome were found to be significantly associated with the diseases under study On the other hand, to balance the genetic effect between two sexes, X chromosome inactivation occurs in most of X-linked genes by silencing one copy of two X chromosomes in females and dosage compensation is achieved A few association studies on X chromosome incorporated the information on dosage compensation However, some of them require the assumption of Hardy-Weinberg equilibrium and some need to specify the underlying genetic model Therefore, in this article, we propose a novel method for association by taking account of different dosage compensation patterns The proposed test is a robust approach because it requires neither specifying the underlying genetic models nor the assumption of Hardy-Weinberg equilibrium Further, the proposed method allows for different deviations from Hardy-Weinberg equilibrium between cases and controls Simulation results demonstrate that our proposed method generally outperforms the existing methods in terms of controlling the size and the test power Finally, we apply the proposed test to the meta-analysis of the Graves' disease data for its practical use

X-Y-autosome translocation, chromosome compaction, NOR expression and heterochromatin insulation in the Scarabaeid beetle Dynastes hercules hercules.

Abstract: The karyotype of the giant beetle Dynastes hercules hercules is composed of only 16 autosomes and large sex chromosomes Meiotic studies in the males showed that a large part of the sex chromosomes undergo synapsis at pachynema similarly to autosomes, demonstrating that both derived from an autosome-gonosome translocation Therefore, karyotype formula is 18,neoXY The heterochromatisation of the neoX short arm at pachynema indicates that it corresponds to the ancestral X It carries the nucleolar organizer region (NOR) in its proximal part, which is undercondensed, especially in male mitotic and meiotic cells In female mitotic cells, both NOR staining and undercondensation were more difficult to observe in the neoX short arms In somatic interphase nuclei, NOR expression strongly varies with the sex Two separated compact groups of silver dots were observed in female nuclei, while a single dispersed and large group of silver deposit exists in the males Both the lower condensation and the higher NOR expression of the single neoX of the males, compared to each of the two neoXs of the females, is interpreted to be a consequence of dosage compensation, a mechanism not yet described in Coleoptera In mammals as well as in Coleoptera, the carriers of gonosome-autosome translocations not exhibiting deleterious phenotypes show constitutive heterochromatin at the autosome-gonosome junction Thus, heterochromatin may play an important universal role by clearly separating chromosome segments with different regulations of gene expression, such as inactivation or dosage compensation of the X chromosome on the one side and a conventional autosomal structure on the other side