Topic
Dosage compensation
About: Dosage compensation is a research topic. Over the lifetime, 1920 publications have been published within this topic receiving 124589 citations.
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TL;DR: The finding of strongly reduced mRNA levels in upd(15)mat cells of the gene encoding secretogranin II (SCG2), which is a precursor of the dopamine releasing factor secretoneurin, raises the question whether hyperphagia in patients with PWS might be due to a defect in dopamine-modulated food reward circuits.
Abstract: Although uniparental disomy often results from the postzygotic rescue of a meiotic non-disjunction event, mosaicism is usually confined to the placenta. We describe a girl with Prader-Willi syndrome (PWS) who is mosaic for normal cells and cells with maternal uniparental disomy 15 [upd(15)mat] in blood and skin. Somatic mosaicism was confirmed by cloning and genotyping of skin fibroblasts. X inactivation studies indicated that upd occurred prior to X inactivation. RNA samples from the cloned cells were used in DNA microarray experiments to study the effect of upd(15)mat on the gene expression pattern of fibroblasts. Proof of principle was obtained by detecting several chromosome 15 genes known to be imprinted. We did not obtain any evidence for novel 15q genes showing imprinted expression in fibroblasts. Differentially expressed genes on other chromosomes are candidates for downstream genes regulated by an imprinted gene and may play a role in the pathogenesis of PWS. The finding of strongly reduced mRNA levels in upd(15)mat cells of the gene encoding secretogranin II (SCG2), which is a precursor of the dopamine releasing factor secretoneurin, raises the question whether hyperphagia in patients with PWS might be due to a defect in dopamine-modulated food reward circuits.
38 citations
TL;DR: incipient speciation, manifest as hybrid sterility when "varieties" are crossed, would appear at the earliest stage in the heterogametic sex, even in genera with homomorphic sex chromosomes (Haldane's rule for Hybrid sterility), and it has been proposed that Haldane’s rule for hybrid inviability needs differences in dosage compensation, so could not apply to generaWith homomorphicsex chromosomes.
38 citations
TL;DR: It is shown that absence of maternally provided SU(VAR)3-7 renders dosage compensation toxic in males, and that global amounts of heterochromatin affect viability of ectopic MSL2-expressing females, bringing to light a link between heterochromeatin and dosage compensation.
Abstract: In Drosophila, dosage compensation augments X chromosome-linked transcription in males relative to females. This process is achieved by the Dosage Compensation Complex (DCC), which associates specifically with the male X chromosome. We previously found that the morphology of this chromosome is sensitive to the amounts of the heterochromatin-associated protein SU(VAR)3-7. In this study, we examine the impact of change in levels of SU(VAR)3-7 on dosage compensation. We first demonstrate that the DCC makes the X chromosome a preferential target for heterochromatic markers. In addition, reduced or increased amounts of SU(VAR)3-7 result in redistribution of the DCC proteins MSL1 and MSL2, and of Histone 4 acetylation of lysine 16, indicating that a wild-type dose of SU(VAR)3-7 is required for X-restricted DCC targeting. SU(VAR)3-7 is also involved in the dosage compensated expression of the X-linked white gene. Finally, we show that absence of maternally provided SU(VAR)3-7 renders dosage compensation toxic in males, and that global amounts of heterochromatin affect viability of ectopic MSL2-expressing females. Taken together, these results bring to light a link between heterochromatin and dosage compensation.
38 citations
TL;DR: The number of sex chromosomes in male and female larvae is discussed in relation to sex determination and the production of monogenous progenies.
Abstract: The somatic haploid chromosome set of the Hessian fly, Mayetiola destructor (Say),consists of two autosomes and two sex chromosomes. Female somatic cells have pairs of each of these chromosomes (2n = 8). Male somatic cells have two pairs of autosomes and two monosomic sex chromosomes. C-banding revealed pericentromeric heterochromatin on one arm of each chromosome. Mitotic chromosomes were karyotyped using relative lengths, centromeric positions, presence of secondary constrictions, and position and length of C-positive regions. Silver nitrate stained pericentromeric, heterochromatic regions on all four chromosomes but did not stain the entire C-positive regions. In female larvae, four distinct polytene chromosomes were found in the basal region cells of the salivary glands. In male larvae, two distinct and two diffuse polytene chromosomes were found in basal region cells. Differential polytene chromosome morphology in male and female larvae, polytene chromosome indexes, and the position of the nucleolus were used to establish correlations between mitotic and polytene chromosomes. The diffuse morphology of the polytene sex chromosomes in male larvae was probably related to dosage compensation. The number of sex chromosomes in male and female larvae is discussed in relation to sex determination and the production of monogenous progenies.
38 citations
TL;DR: A comprehensive review of the occurrence of XY females and XX males in the mouse has recently been published by Eicher and it is shown that these situations are common and associated with various types of intersexual development.
38 citations