The Haplolethal Region at the 16F Gene Cluster of Drosophila melanogaster: Structure and Function

Abstract Extensive aneuploid analyses had shown the existence of a few haplolethal (HL) regions and one triplolethal region in the genome of Drosophila melanogaster. Since then, only two haplolethals, 22F1-2 and 16F, have been directly linked to identified genes, dpp and wupA, respectively. However, with the possible exception of dpp, the actual bases for this dosage sensitivity remain unknown. We have generated and characterized dominant-lethal mutations and chromosomal rearrangements in 16F and studied them in relation to the genes in the region. This region extends along 100 kb and includes at least 14 genes. The normal HL function depends on the integrity of a critical 4-kb window of mostly noncoding sequences within the wupA transcription unit that encodes the muscle protein troponin I (TNI). All dominant lethals are breakpoints within that window, which prevent the functional expression of TNI and other adjacent genes in the proximal direction. However, independent mutations in these genes result in recessive lethal phenotypes only. We propose that the HL at 16F represents a long-range cis regulatory region that acts upon a number of functionally related genes whose combined haploidy would yield the dominant-lethal effect.

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Beneficial Effects of Resveratrol in Mouse Gastrocnemius: A Hint to Muscle Phenotype and Proteolysis

Cells ◽

10.3390/cells10092436 ◽

2021 ◽

Vol 10 (9) ◽

pp. 2436

Author(s):

Laura Mañas-García ◽

Charlotte Denhard ◽

Javier Mateu ◽

Xavier Duran ◽

Joaquim Gea ◽

...

Keyword(s):

Signaling Pathways ◽

Muscle Fiber ◽

Troponin I ◽

Muscle Protein ◽

Strength Loss ◽

Muscle Weight ◽

Cross Sectional ◽

Therapeutic Implications ◽

Resveratrol Treatment ◽

And Function

We hypothesized that the phenolic compound resveratrol mitigates muscle protein degradation and loss and improves muscle fiber cross-sectional area (CSA) in gastrocnemius of mice exposed to unloading (7dI). In gastrocnemius of mice (female C57BL/6J, 10 weeks) exposed to a seven-day period of hindlimb immobilization with/without resveratrol treatment, markers of muscle proteolysis (tyrosine release, systemic troponin-I), atrophy signaling pathways, and muscle phenotypic features and function were analyzed. In gastrocnemius of unloaded mice treated with resveratrol, body and muscle weight and function were attenuated, whereas muscle proteolysis (tyrosine release), proteolytic and apoptotic markers, atrophy signaling pathways, and myofiber CSA significantly improved. Resveratrol treatment of mice exposed to a seven-day period of unloading prevented body and muscle weight and limb strength loss, while an improvement in muscle proteolysis, proteolytic markers, atrophy signaling pathways, apoptosis, and muscle fiber CSA was observed in the gastrocnemius muscle. These findings may have potential therapeutic implications in the management of disuse muscle atrophy in clinical settings.

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Muscle Phenotype, Proteolysis, and Atrophy Signaling During Reloading in Mice: Effects of Curcumin on the Gastrocnemius

Nutrients ◽

10.3390/nu12020388 ◽

2020 ◽

Vol 12 (2) ◽

pp. 388 ◽

Cited By ~ 3

Author(s):

Laura Mañas-García ◽

Nuria Bargalló ◽

Joaquim Gea ◽

Esther Barreiro

Keyword(s):

Protein Synthesis ◽

Signaling Pathways ◽

Muscle Function ◽

Histone Deacetylases ◽

Troponin I ◽

Muscle Protein ◽

Sirtuin 1 ◽

Hybrid Fibers ◽

Disuse Muscle Atrophy ◽

And Function

We hypothesized that curcumin may mitigate muscle protein degradation and loss through attenuation of proteolytic activity in limb muscles of mice exposed to reloading (7dR) following immobilization (7dI). In gastrocnemius of mice (female C57BL/6J, 10 weeks) exposed to recovery following a seven-day period of hindlimb immobilization with/without curcumin treatment, markers of muscle proteolysis (systemic troponin-I), atrophy signaling pathways and histone deacetylases, protein synthesis, and muscle phenotypic characteristics and function were analyzed. In gastrocnemius of reloading mice compared to unloaded, muscle function, structure, sirtuin-1, and protein synthesis improved, while proteolytic and signaling markers (FoxO1/3) declined. In gastrocnemius of unloaded and reloaded mice treated with curcumin, proteolytic and signaling markers (NF-kB p50) decreased and sirtuin-1 activity and hybrid fibers size increased (reloaded muscle), while no significant improvement was seen in muscle function. Treatment with curcumin elicited a rise in sirtuin-1 activity, while attenuating proteolysis in gastrocnemius of mice during reloading following a period of unloading. Curcumin attenuated muscle proteolysis probably via activation of histone deacetylase sirtuin-1, which also led to decreased levels of atrophy signaling pathways. These findings offer an avenue of research in the design of therapeutic strategies in clinical settings of patients exposed to periods of disuse muscle atrophy.

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Cis and trans interactions between the iab regulatory regions and abdominal-A and abdominal-B in Drosophila melanogaster.

Genetics ◽

10.1093/genetics/139.2.835 ◽

1995 ◽

Vol 139 (2) ◽

pp. 835-848 ◽

Cited By ~ 3

Author(s):

J E Hendrickson ◽

S Sakonju

Keyword(s):

Drosophila Melanogaster ◽

Chromosomal Rearrangements ◽

Transcription Unit ◽

Homeotic Genes ◽

Regulatory Regions ◽

In Trans ◽

Trans Regulation ◽

Cis And Trans ◽

In Cis ◽

Target Promoter

Abstract The infra-abdominal (iab) elements in the bithorax complex of Drosophila melanogaster regulate the transcription of the homeotic genes abdominal-A (abd-A) and Abdominal-B (Abd-B) in cis. Here we describe two unusual aspects of regulation by the iab elements, revealed by an analysis of an unexpected complementation between mutations in the Abd-B transcription unit and these regulatory regions. First, we find that iab-6 and iab-7 can regulate Abd-B in trans. This iab trans regulation is insensitive to chromosomal rearrangements that disrupt transvection effects at the nearby Ubx locus. In addition, we show that a transposed Abd-B transcription unit and promoter on the Y chromosome can be activated by iab elements located on the third chromosome. These results suggest that the iab regions can regulate their target promoter located at a distant site in the genome in a manner that is much less dependent on homologue pairing than other transvection effects. The iab regulatory regions may have a very strong affinity for the target promoter, allowing them to interact with each other despite the inhibitory effects of chromosomal rearrangements. Second, by generating abd-A mutations on rearrangement chromosomes that break in the iab-7 region, we show that these breaks induce the iab elements to switch their target promoter from Abd-B to abd-A. These two unusual aspects of iab regulation are related by the iab-7 breakpoint chromosomes that prevent iab elements from acting on Abd-B and allow them to act on abd-A. We propose that the iab-7 breaks prevent both iab trans regulation and target specificity by disrupting a mechanism that targets the iab regions to the Abd-B promoter.

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Genetical and Cytological Studies of Lethals induced by Chemical Treatment in Drosophila melanogaster.

Proceedings of the Royal Society of Edinburgh Section B Biology ◽

10.1017/s0080455x00130000 ◽

1945 ◽

Vol 62 (3) ◽

pp. 234-242 ◽

Cited By ~ 2

Author(s):

Helen Slizynska ◽

B. M. Slizynski

Keyword(s):

Drosophila Melanogaster ◽

X Chromosome ◽

Chemical Treatment ◽

Structural Changes ◽

Chromosomal Rearrangements ◽

Point Mutations ◽

Ultra Violet ◽

Lethal Effect ◽

Structural Elements ◽

Adult Males

The present paper forms a continuation of studies of recessive sex-linked lethals in Drosophila melanogaster published previously (1938, 1941). In these, lethals occurring spontaneously, induced by X-ray treatment and by ultra-violet light were examined cytologically in the salivary gland chromosomes.The genetic factors which stop or change the development of an individual in such a way that its death ensues under normal conditions are termed lethals. A lethal effect may be connected with a mutation of a gene or with its absence from the chromosome: those which cannot be proved to be associated with the absence of a cytologically detectable part of the chromosome are considered as due to “point” mutations.The absence of a microscopically identifiable section of a chromosome with all its genetical and structural elements is called a deficiency. With few exceptions (Muller, 1935; Demerec and Hoover, 1936) the deficiencies in the X-chromosome, whatever their size and whatever loci they involve, are lethal for males. In females heterozygous for them deficiencies of small or even moderate size usually do not produce any visible phenotypical effect, although some cases are known (Mohr, 1923; Slizynska, 1938) in which a heterozygous deficiency for a particular band is always associated with a definite phenotype. Thus a lethal effect may or may not be the result of a deficiency, while a deficiency in the X-chromosome almost always has a lethal effect in the males.In 1941 Auerbach (1943, 1946 in press) succeeded in producing “visible” and lethal mutations and chromosomal rearrangements by chemical treatment in which adult males were exposed to vapours of (C1CH2CH2)2S in a specially designed apparatus. The object of this paper is to show what proportion of sex-linked recessive lethals produced in Drosophila melanogaster by these new agents is connected with detectable deficiencies. Besides finding out whether chemically produced lethals are associated with detectable deficiencies, the problem of the relation between lethals and “visible” mutations is discussed on the basis of their respective distributions along the chromosome. It should be stated that the lethals connected with gross structural changes represent probably only a small fraction of such lethals actually produced since many of them were eliminated by zygotic lethality.

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Molecular and genetic characterization of the Drosophila melanogaster 87E actin gene region.

Genetics ◽

10.1093/genetics/119.2.407 ◽

1988 ◽

Vol 119 (2) ◽

pp. 407-420

Author(s):

L J Manseau ◽

B Ganetzky ◽

E A Craig

Keyword(s):

Drosophila Melanogaster ◽

Muscle Protein ◽

Transcription Unit ◽

Complementation Group ◽

Actin Gene ◽

Induced Mutations ◽

Coding Region ◽

Protein Coding ◽

Recessive Lethal ◽

Mutagenesis Screen

Abstract A combined molecular and genetic analysis of the 87E actin gene (Act87E) in Drosophila melanogaster was undertaken. A clone of Act87E was isolated and characterized. The Act87E transcription unit is 1.57 kb and includes a 556-base intervening sequence in the 5' leader of the gene. The protein-coding region is contiguous and encodes a protein that is greater than 93% identical to the other Drosophila actins. By in situ hybridization with a series of deficiencies that break in 87E, Act87E was localized to a region encompassing one to three faint, polytene chromosome bands. The region between the deficiency endpoints that flank the actin gene was isolated and measures approximately 24-30 kb. The closest proximal deficiency endpoint lies 8-10 kb 5' to the actin gene; the closest distal deficiency endpoint lies 16-20 kb 3' to the actin gene. A single, recessive lethal complementation group lies between the deficiency endpoints that flank the actin gene. An EMS mutagenesis screen produced four additional members of this recessive lethal complementation group. Molecular analysis of the members of this complementation group indicated that two of the newly induced mutations have deletions of approximately 1 kb in a transcribed region 4-5 kb 3' (distal) to the actin gene. This result suggests that the recessive lethal complementation group represents a gene separate from and distal to the actin gene. The mutagenesis screen failed to identify additional recessive lethal complementation groups in the actin gene-containing region. The implications of the failure to identify recessive lethal mutations in the actin gene are discussed in reference to studies of other conserved multigene families and other muscle protein mutations.

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The Alcohol Dehydrogenase Gene Is Nested in the outspread Locus of Drosophila melanogaster

Genetics ◽

10.1093/genetics/143.2.897 ◽

1996 ◽

Vol 143 (2) ◽

pp. 897-911 ◽

Cited By ~ 1

Author(s):

S McNabb ◽

S Greig ◽

T Davis

Keyword(s):

Drosophila Melanogaster ◽

Alcohol Dehydrogenase ◽

Pcr Amplification ◽

Transcription Unit ◽

Adjacent Gene ◽

Dehydrogenase Gene ◽

Chromosomal Breakpoints ◽

Splicing Patterns ◽

Somatic Musculature

Abstract This report describes the structure and expression of the outspread (osp) gene of Drosophila melanogaster. Previous work showed that chromosomal breakpoints associated with mutations of the osp locus map to both sides of the alcohol dehydrogenase gene (Adh), suggesting that Adh and the adjacent gene Adh' are nested in osp. We extended a chromosomal walk and mapped additional osp mutations to define the maximum molecular limit of osp as 119 kb. We identified a 6-kb transcript that hybridizes to osp region DNA and is altered or absent in osp mutants. Accumulation of this RNA peaks during embryonic and pupal periods. The osp cDNAs comprise two distinct classes based on alternative splicing patterns. The 5′ end of the longest cDNA was extended by PCR amplification. When hybridized to the osp walk, the 5′ extension verifies that Adh and Adh' are nested in osp and shows that osp has a transcription unit of ≥74 kb. In situ hybridization shows that osp is expressed both maternally and zygotically. In the ovary, osp is transcribed in nurse cells and localized in the oocyte. In embryos, expression is most abundant in the developing visceral and somatic musculature.

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The Drosophila engrailed and invected Genes: Partners in Regulation, Expression and Function

Genetics ◽

10.1093/genetics/142.3.893 ◽

1996 ◽

Vol 142 (3) ◽

pp. 893-906 ◽

Cited By ~ 3

Author(s):

Elizabeth Gustavson ◽

Andrew S Goldsborough ◽

Zehra Ali ◽

Thomas B Kornberg

Keyword(s):

Expression Pattern ◽

Cultured Cells ◽

Regulatory Region ◽

Embryonic Lethality ◽

Wild Type ◽

Terminal Portion ◽

Coding Sequence ◽

Differential Effects ◽

And Function ◽

Redundant Functions

Abstract We isolated and characterized numerous engrailed and invected alleles. Among the deficiencies we isolated, a mutant lacking invected sequences was viable and phenotypically normal, a mutant lacking engrailed was an embryo lethal and had slight segmentation defects, and a mutant lacking both engrailed and invected was most severely affected. In seven engrailed alleles, mutations caused translation to terminate prematurely in the central or C-terminal portion of the coding sequence, resulting in embryonic lethality and segmentation defects. Both engrailed and invected expression declined prematurely in these mutant embryos. In wild-type embryos, engrailed and invected are juxtaposed and are expressed in essentially identical patterns. A breakpoint mutant that separates the mgrailed and invected transcription units parceled different aspects of the expression pattern to engrailed or invected. We also found that both genes cause similar defects when expressed ectopically and that the protein products of both genes act to repress transcription in cultured cells. We propose that the varied phenotypes of the engrailed alleles can be explained by the differential effects these mutants have on the combination of engrailed and invected activities, that engrailed and invected share a regulatory region, and that they encode redundant functions.

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Transvection at the End of the Truncated Chromosome in Drosophila melanogaster

Genetics ◽

10.1093/genetics/163.4.1375 ◽

2003 ◽

Vol 163 (4) ◽

pp. 1375-1387

Author(s):

Mikhail Savitsky ◽

Tatyana Kahn ◽

Ekaterina Pomerantseva ◽

Pavel Georgiev

Keyword(s):

Drosophila Melanogaster ◽

Homologous Chromosome ◽

Regulatory Region ◽

Proximal Region ◽

The Other ◽

Upstream Region ◽

Upstream Sequence ◽

Transcription Start ◽

Promoter Proximal Region

Abstract The phenomenon of transvection is well known for the Drosophila yellow locus. Thus enhancers of a promoterless yellow locus in one homologous chromosome can activate the yellow promoter in the other chromosome where the enhancers are inactive or deleted. In this report, we examined the requirements for trans-activation of the yellow promoter at the end of the deficient chromosome. A number of truncated chromosomes ending in different areas of the yellow regulatory region were examined in combination with the promoterless y alleles. We found that trans-activation of the yellow promoter at the end of a deficient chromosome required ∼6 kb of an additional upstream sequence. The nature of upstream sequences affected the strength of transvection: addition of gypsy sequences induced stronger trans-activation than addition of HeT-A or yellow sequences. Only the promoter proximal region (within -158 bp of the yellow transcription start) was essential for trans-activation; i.e., transvection did not require extensive homology in the yellow upstream region. Finally, the yellow enhancers located on the two pairing chromosomes could cooperatively activate one yellow promoter.

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A Family of Genes Clustered at the Triplo-lethal Locus of Drosophila melanogaster Has an Unusual Evolutionary History and Significant Synteny With Anopheles gambiae

Genetics ◽

10.1093/genetics/165.2.613 ◽

2003 ◽

Vol 165 (2) ◽

pp. 613-621 ◽

Cited By ~ 2

Author(s):

Douglas R Dorer ◽

Jamie A Rudnick ◽

Etsuko N Moriyama ◽

Alan C Christensen

Keyword(s):

Phylogenetic Analysis ◽

Drosophila Melanogaster ◽

Anopheles Gambiae ◽

Evolutionary History ◽

Codon Bias ◽

Good Target ◽

The Family ◽

Genes Encoding ◽

And Function ◽

Gambiae Genome

Abstract Within the unique Triplo-lethal region (Tpl) of the Drosophila melanogaster genome we have found a cluster of 20 genes encoding a novel family of proteins. This family is also present in the Anopheles gambiae genome and displays remarkable synteny and sequence conservation with the Drosophila cluster. The family is also present in the sequenced genome of D. pseudoobscura, and homologs have been found in Aedes aegypti mosquitoes and in four other insect orders, but it is not present in the sequenced genome of any noninsect species. Phylogenetic analysis suggests that the cluster evolved prior to the divergence of Drosophila and Anopheles (250 MYA) and has been highly conserved since. The ratio of synonymous to nonsynonymous substitutions and the high codon bias suggest that there has been selection on this family both for expression level and function. We hypothesize that this gene family is Tpl, name it the Osiris family, and consider possible functions. We also predict that this family of proteins, due to the unique dosage sensitivity and the lack of homologs in noninsect species, would be a good target for genetic engineering or novel insecticides.

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