DOSAGE COMPENSATION OF SERINE-4 TRANSFER RNA IN DROSOPHILA MELANOGASTER

ABSTRACT A dosage series of the X chromosome site for serine-4 transfer RNA consisting of one of three copies in females and one to two in males was constructed to test whether transfer RNA expression is governed by dosage compensation. A dosage effect on the level of the serine-4 isoacceptor was observed in both females and males when the structural locus was varied. However, in males, each dose had a relatively greater expression so the normal one dose was slightly greater than the total female value and the duplicated male had the highest relative expression of all the types examined. Serine-4 levels in males and females from an isogenic Oregon-R stock were similar. Thus the transfer RNA levels conform to the expectations of dosage compensation.

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Quantitative Genetics of Drosophila Melanogaster. II. Heritabilities and Genetic Correlations between Sexes for Head and Thorax Traits.

Genetics ◽

10.1093/genetics/119.2.421 ◽

1988 ◽

Vol 119 (2) ◽

pp. 421-433

Author(s):

D E Cowley ◽

W R Atchley

Keyword(s):

Drosophila Melanogaster ◽

Sexual Dimorphism ◽

Genetic Analysis ◽

X Chromosome ◽

Dosage Compensation ◽

Imaginal Disc ◽

Genetic Correlations ◽

Body Parts ◽

Quantitative Genetic ◽

Males And Females

Abstract A quantitative genetic analysis is reported for traits on the head and thorax of adult fruit flies, Drosophila melanogaster. Females are larger than males, and the magnitude of sexual dimorphism is similar for traits derived from the same imaginal disc, but the level of sexual dimorphism varies widely across discs. The greatest difference between males and females occurs for the dimensions of the sclerotized mouthparts of the proboscis. Most of the traits studied are highly heritable with heritabilities ranging from 0.26 to 0.84 for males and 0.27 to 0.81 for females. In general, heritabilities are slightly higher for males, possibly reflecting the effect of dosage compensation on X-linked variance. The X chromosome contributes substantially to variance for many of these traits, and including results reported elsewhere, the variance for over two-thirds of the traits studied includes X-linked variance. The genetic correlations between sexes for the same trait are generally high and close to unity. Coupled with the small differences in the traits between sexes for heritabilities and phenotypic variances, these results suggest that selection would be very slow to change the level of sexual dimorphism in size of various body parts.

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Expression of cis-regulatory mutations of the white locus in metafemales of Drosophila melanogaster

Genetics Research ◽

10.1017/s0016672300030123 ◽

1992 ◽

Vol 59 (1) ◽

pp. 11-18 ◽

Cited By ~ 17

Author(s):

James A. Birchler

Keyword(s):

X Chromosome ◽

Dosage Compensation ◽

Phenotypic Expression ◽

Inverse Correlation ◽

Basic Mechanism ◽

Altered Expression ◽

Regulatory Mutations ◽

Sexually Dimorphic Expression ◽

White Locus ◽

Males And Females

SummaryAt the white eye colour locus, there are a number of alleles that have altered expression between males and females. To test these regulatory mutations of the white eye colour locus for their phenotypic expression in metafemales (3X; 2A) compared to diploid females and males, eleven alleles or transduced copies of white were analysed. Two alleles that exhibit dosage compensation between males and females (apricot, blood) also exhibit dosage compensation in metafemales. White-ivory and white-eosin, which fail to dosage compensate in males compared to females, but that are distinct physical lesions, also show a dosage effect in metafemales. Two alleles with greater expression in males than females (spotted, spotted-55) exhibit even lower expression in metafemales. Lastly, five transduced copies of white carrying three different lengths of the white promoter, but that all exhibit higher expression in males, show reduced expression in metafemales, exhibiting an inverse correlation between the level of expression and the dosage of the X chromosome. Because these alleles of white respond to dosage compensation in metafemales as a continuum of the male and female responses, it is concluded that the same basic mechanism of dosage compensation is involved and that the dosage of the X chromosome conditions the sexually dimorphic expression.

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Chromosomal basis of dosage compensation in Drosophila: I. Cellular autonomy of hyperactivity of the male X-chromosome in salivary glands and sex differentiation

Genetics Research ◽

10.1017/s001667230000197x ◽

1969 ◽

Vol 14 (2) ◽

pp. 137-150 ◽

Cited By ~ 43

Author(s):

S. C. Lakhotia ◽

A. S. Mukherjee

Keyword(s):

Drosophila Melanogaster ◽

Salivary Glands ◽

X Chromosome ◽

Metabolic Activity ◽

Dosage Compensation ◽

Rna Synthesis ◽

Sex Differentiation ◽

Chromosome 3 ◽

Normal Male ◽

Developmental Physiology

Morphology and the rate of RNA synthesis of the X-chromosome in XX/XO mosaic larval salivary glands of Drosophila melanogaster have been examined. For this purpose the unstable ring-X was utilized to produce XX and XO nuclei in the same pair of glands. The width of the X-chromosome and the left arm of the 3rd chromosome (3L) of larval salivary glands was measured and the rate of RNA synthesis by them was studied upon the use of [3H]uridine autoradiography in such XX (female) and XO (male) nuclei developing in a female background (i.e. otherwise genotypically XX). In such mosaic glands the width of the single X-chromosome of male nuclei is nearly as great as that of the paired two X's of female nuclei, as is also the case in normal male (X Y) and female (XX). The single X of male nuclei synthesizes RNA at a rate equal to that of the paired two X's of female nuclei and nearly twice that of an unpaired X of XX nuclei. Neither the developmental physiology of the sex nor the proportion of XO nuclei in a pair of mosaic salivary glands of an XX larva has any influence on these two characteristics of the male X-chromosome.It is suggested that dosage compensation in Drosophila is achieved chiefly, if not fully, by a hyperactivity of the male X, in contrast to the single X inactivation in female mammals, that this hyperactivity of the male X is expressed visibly in the morphology and metabolic activity of the X-chromosome in the larval salivary glands of the male, and that this hyperactivity and therefore dosage compensation in Drosophila in general is not dependent on sex-differentiation, but is a function of the doses of the X-chromosome itself.

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Drosophila CLAMP is an essential protein with sex-specific roles in males and females

10.1101/042820 ◽

2016 ◽

Author(s):

Jennifer A. Urban ◽

Caroline A. Doherty ◽

William T. Jordan ◽

Jacob E. Bliss ◽

Jessica Feng ◽

...

Keyword(s):

X Chromosome ◽

Dosage Compensation ◽

Zinc Finger Protein ◽

Pericentric Heterochromatin ◽

Single Male ◽

Essential Protein ◽

Msl Complex ◽

Males And Females ◽

Male Specific

AbstractDosage compensation is a fundamental mechanism in many species that corrects for the inherent imbalance in X-chromosome copy number between XY males and XX females. In Drosophila melanogaster, transcriptional output from the single male X-chromosome is equalized to that of XX females by recruitment of the Male Specific Lethal (MSL) complex to specific sequences along the length of the X-chromosome. The initial recruitment of MSL complex to the X-chromosome is dependent on a recently discovered zinc finger protein called Chromatin-Linked Adapter for MSL Proteins (CLAMP). However, further studies on the in vivo function of CLAMP remained difficult because the location of the gene in pericentric heterochromatin made it challenging to create null mutations or deficiencies. Using the CRISPR/Cas9 genome editing system, we generated the first null mutant in the clamp gene that eliminates expression of CLAMP protein. We show that CLAMP is necessary for both male and female viability. While females die at the third instar larval stage, males die earlier, likely due to the essential role of CLAMP in male dosage compensation. Moreover, we demonstrate that CLAMP promotes dosage compensation in males and represses key male-specific transcripts involved in sex-determination in females. Our results reveal that CLAMP is an essential protein with dual roles in males and females, which together assure that dosage compensation is a sex-specific process.

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Autosomal and X-Linked Additive Genetic Variation for Lifespan and Aging: Comparisons Within and Between the Sexes in Drosophila melanogaster

G3 Genes|Genome|Genetics ◽

10.1534/g3.116.028308 ◽

2016 ◽

Vol 6 (12) ◽

pp. 3903-3911 ◽

Cited By ~ 7

Author(s):

Robert M Griffin ◽

Holger Schielzeth ◽

Urban Friberg

Keyword(s):

Drosophila Melanogaster ◽

Genetic Variation ◽

X Chromosome ◽

Dosage Compensation ◽

Genetic Variance ◽

Additive Genetic Variance ◽

Conclusive Evidence ◽

Substitution Lines ◽

Chromosome Substitution Lines ◽

Sexually Antagonistic Selection

Abstract Theory makes several predictions concerning differences in genetic variation between the X chromosome and the autosomes due to male X hemizygosity. The X chromosome should: (i) typically show relatively less standing genetic variation than the autosomes, (ii) exhibit more variation in males compared to females because of dosage compensation, and (iii) potentially be enriched with sex-specific genetic variation. Here, we address each of these predictions for lifespan and aging in Drosophila melanogaster. To achieve unbiased estimates of X and autosomal additive genetic variance, we use 80 chromosome substitution lines; 40 for the X chromosome and 40 combining the two major autosomes, which we assay for sex-specific and cross-sex genetic (co)variation. We find significant X and autosomal additive genetic variance for both traits in both sexes (with reservation for X-linked variation of aging in females), but no conclusive evidence for depletion of X-linked variation (measured through females). Males display more X-linked variation for lifespan than females, but it is unclear if this is due to dosage compensation since also autosomal variation is larger in males. Finally, our results suggest that the X chromosome is enriched for sex-specific genetic variation in lifespan but results were less conclusive for aging overall. Collectively, these results suggest that the X chromosome has reduced capacity to respond to sexually concordant selection on lifespan from standing genetic variation, while its ability to respond to sexually antagonistic selection may be augmented.

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A Role for siRNA in X-Chromosome Dosage Compensation in Drosophila melanogaster

Genetics ◽

10.1534/genetics.112.140236 ◽

2012 ◽

Vol 191 (3) ◽

pp. 1023-1028 ◽

Cited By ~ 28

Author(s):

Debashish U. Menon ◽

Victoria H. Meller

Keyword(s):

Drosophila Melanogaster ◽

X Chromosome ◽

Dosage Compensation

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LACK OF DOSAGE COMPENSATION FOR AN AUTOSOMAL GENE RELOCATED TO THE X CHROMOSOME IN DROSOPHILA MELANOGASTER

Genetics ◽

10.1093/genetics/85.3.489 ◽

1977 ◽

Vol 85 (3) ◽

pp. 489-496

Author(s):

Richard L Roehrdanz ◽

James M Kitchens ◽

John C Lucchesi

Keyword(s):

Drosophila Melanogaster ◽

Experimental Evidence ◽

Structural Gene ◽

X Chromosome ◽

Dosage Compensation ◽

Oxidase Activity ◽

Aldehyde Oxidase ◽

Autosomal Gene

ABSTRACT Aldehyde oxidase activity has been measured in flies with the structural gene for this enzyme translocated to the X chromosome. These measurements are presented as experimental evidence that, in Drosophila melanogaster, an autosomal gene relocated to the X chromosome is not dosage compensated.

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Transposon insertions causing constitutive Sex-lethal activity in Drosophila melanogaster affect Sxl sex-specific transcript splicing.

Genetics ◽

10.1093/genetics/139.2.631 ◽

1995 ◽

Vol 139 (2) ◽

pp. 631-648

Author(s):

M Bernstein ◽

R A Lersch ◽

L Subrahmanyan ◽

T W Cline

Keyword(s):

Drosophila Melanogaster ◽

X Chromosome ◽

Dosage Compensation ◽

Rna Splicing ◽

Wild Type ◽

Gain Of Function ◽

Positive Regulators ◽

Sex Lethal ◽

Male Specific ◽

Transposon Insertions

Abstract Sex-lethal (Sxl) gene products induce female development in Drosophila melanogaster and suppress the transcriptional hyperactivation of X-linked genes responsible for male X-chromosome dosage compensation. Control of Sxl functioning by the dose of X-chromosomes normally ensures that the female-specific functions of this developmental switch gene are only expressed in diplo-X individuals. Although the immediate effect of X-chromosome dose is on Sxl transcription, during most of the life cycle "on" vs. "off" reflects alternative Sxl RNA splicing, with the female (productive) splicing mode maintained by a positive feedback activity of SXL protein on Sxl pre-mRNA splicing. "Male-lethal" (SxlM) gain-of-function alleles subvert Sxl control by X-chromosome dose, allowing female Sxl functions to be expressed independent of the positive regulators upstream of Sxl. As a consequence, SxlM haplo-X animals (chromosomal males) die because of improper dosage compensation, and SxlM chromosomal females survive the otherwise lethal effects of mutations in upstream positive regulators. Five independent spontaneous SxlM alleles were shown previously to be transposon insertions into what was subsequently found to be the region of regulated sex-specific Sxl RNA splicing. We show that these five alleles represent three different mutant types: SxlM1, SxlM3, and SxlM4. SxlM1 is an insertion of a roo element 674 bp downstream of the translation-terminating male-specific exon. SxlM3 is an insertion of a hobo transposon (not 297 as previously reported) into the 3' splice site of the male exon, and SxlM4 is an insertion of a novel transposon into the male-specific exon itself. We show that these three gain-of-function mutants differ considerably in their ability to bypass the sex determination signal, with SxlM4 being the strongest and SxlM1 the weakest. This difference is also reflected in effects of these mutations on sex-specific RNA splicing and on the rate of appearance of SXL protein in male embryos. Transcript analysis of double-mutant male-viable SxlM derivatives in which the SxlM insertion is cis to loss-of-function mutations, combined with other results reported here, indicates that the constitutive character of these SxlM alleles is a consequence of an alteration of the structure of the pre-mRNA that allows some level of female splicing to occur even in the absence of functional SXL protein. Surprisingly, however, most of the constitutive character of SxlM alleles appears to depend on the mutant alleles' responsiveness, perhaps greater than wild-type, to the autoregulatory splicing activity of the wild-type SXL proteins they produce.

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FITNESS EFFECTS OF EMS-INDUCED MUTATIONS ON THE X CHROMOSOME OF DROSOPHILA MELANOGASTER. I. VIABILITY EFFECTS AND HETEROZYGOUS FITNESS EFFECTS

Genetics ◽

10.1093/genetics/87.4.763 ◽

1977 ◽

Vol 87 (4) ◽

pp. 763-774

Author(s):

Joyce A Mitchell

Keyword(s):

Drosophila Melanogaster ◽

X Chromosome ◽

Strongly Correlated ◽

Induced Mutations ◽

X Chromosomes ◽

Heterozygous Condition ◽

Fitness Effects ◽

Sucrose Solutions ◽

Discrete Generation ◽

Males And Females

ABSTRACT Drosophila melanogaster X chromosomes were mutagenized by feeding males sucrose solutions containing ethyl methanesulfonate (EMS); the concentrations of EMS in the food were 2.5 mm, 5.0 mm, and 10.0 mm. Chromosomes were exposed to the mutagen up to three times by treating males in succeeding generations. After treatment, the effective exposures were 2.5, 5.0, 7.5, 10.0, 15.0, and 30.0 mm EMS. X chromosomes treated in this manner were tested for effects on fitness in both hemizygous and heterozygous conditions, and for effects on viability in hemizygous and homozygous conditions. In addition, untreated X chromosomes were available for study. The viability and heterozygous fitness effects are presented in this paper, and the hemizygous fitness effects are discussed in the accompanying one (Mitchell and Simmons 1977). Hemizygous and homozygous viability effects were measured by segregation tests in vial cultures. For hemizygous males, viability was reduced 0.5 percent per mm EMS treatment; for homozygous females, it was reduced 0.7 percent per mm treatment. The decline in viability appeared to be a linear function of EMS dose. The viabilities of males and females were strongly correlated. Heterozygous fitness effects were measured by monitoring changes in the frequencies of treated and untreated X chromosomes in discrete generation populations which, through the use of an X-Y translocation, maintained them only in heterozygous condition. Flies that were heterozygous for a treated chromosome were found to be 0.4 percent less fit per m m EMS than flies heterozygous for an untreated one.

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