scholarly journals Transcriptional Activity of the Telomeric Retrotransposon HeT-A in Drosophila melanogaster Is Stimulated as a Consequence of Subterminal Deficiencies at Homologous and Nonhomologous Telomeres

2007 ◽  
Vol 27 (13) ◽  
pp. 4991-5001 ◽  
Author(s):  
Radmila Capkova Frydrychova ◽  
Harald Biessmann ◽  
Alexander Y. Konev ◽  
Mikhail D. Golubovsky ◽  
Jessica Johnson ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Promoter Activity ◽  
Transcriptional Activity ◽  
Position Effect ◽  
Wild Type ◽  
Global Effect ◽  
Transcript Levels ◽  
Telomere Position Effect

ABSTRACT Drosophila melanogaster telomeres have two DNA domains: a terminal array of retrotransposons and a subterminal repetitive telomere-associated sequence (TAS), a source of telomere position effect (TPE). We reported previously that deletion of the 2L TAS array leads to dominant suppression of TPE by stimulating in trans expression of a telomeric transgene. Here, we compared the transcript activities of a w transgene inserted between the retrotransposon and TAS arrays at the 2L telomere in genotypes with different lengths of the 2L TAS. In contrast to individuals bearing a wild-type 2L homologue, flies with a TAS deficiency showed a significant increase in the level of telomeric w transcript during development, especially in pupae. Moreover, we identified a read-through w transcript initiated from a retrotransposon promoter in the terminal array. Read-through transcript levels also significantly increased with the presence of a 2L TAS deficiency in trans, indicating a stimulating force of the TAS deficiency on retrotransposon promoter activity. The read-through transcript contributes to total w transcript, although most w transcript originates at the w promoter. While silencing of transgenes in nonhomologous telomeres is suppressed by 2L TAS deficiencies, suggesting a global effect, the overall level of HeT-A transcripts is not increased under similar conditions.

scholarly journals Mutational Analysis of a Histone Deacetylase in Drosophila melanogaster: Missense Mutations Suppress Gene Silencing Associated With Position Effect Variegation

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 657-668 ◽  
Author(s):  
Randy Mottus ◽  
Richard E Sobel ◽  
Thomas A Grigliatti
Keyword(s):  
Drosophila Melanogaster ◽  
Histone Deacetylase ◽  
Transcriptional Activity ◽  
Mutational Analysis ◽  
Position Effect ◽  
Transcriptional Regulator ◽  
Position Effect Variegation ◽  
Missense Mutations ◽  
Effect Variegation ◽  
New Mutations

Abstract For many years it has been noted that there is a correlation between acetylation of histones and an increase in transcriptional activity. One prediction, based on this correlation, is that hypomorphic or null mutations in histone deacetylase genes should lead to increased levels of histone acetylation and result in increased levels of transcription. It was therefore surprising when it was reported, in both yeast and fruit flies, that mutations that reduced or eliminated a histone deacetylase resulted in transcriptional silencing of genes subject to telomeric and heterochromatic position effect variegation (PEV). Here we report the first mutational analysis of a histone deacetylase in a multicellular eukaryote by examining six new mutations in HDAC1 of Drosophila melanogaster. We observed a suite of phenotypes accompanying the mutations consistent with the notion that HDAC1 acts as a global transcriptional regulator. However, in contrast to recent findings, here we report that specific missense mutations in the structural gene of HDAC1 suppress the silencing of genes subject to PEV. We propose that the missense mutations reported here are acting as antimorphic mutations that “poison” the deacetylase complex and propose a model that accounts for the various phenotypes associated with lesions in the deacetylase locus.

scholarly journals The petD gene is transcribed by functionally redundant promoters in Chlamydomonas reinhardtii chloroplasts.

1994 ◽  
Vol 14 (9) ◽  
pp. 6171-6179 ◽  
Author(s):  
N R Sturm ◽  
R Kuras ◽  
S Büschlen ◽  
W Sakamoto ◽  
K L Kindle ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Promoter Activity ◽  
Transcriptional Activity ◽  
Transcription Termination ◽  
Cytochrome F ◽  
Direct Repeats ◽  
Wild Type ◽  
Coding Region ◽  
Putative Promoter ◽  
Coding Regions

FUD6, a nonphotosynthetic mutant of Chlamydomonas reinhardtii, was previously found to be deficient in the synthesis of subunit IV of the cytochrome b6/f complex, the chloroplast petD gene product (C. Lemaire, J. Girard-Bascou, F.-A. Wollman, and P. Bennoun, Biochim. Biophys. Acta 851:229-238, 1986). The lesion in FUD6 is a 236-bp deletion between two 11-bp direct repeats in the chloroplast genome. It extends from 82 to 72 bp upstream of the 5' end of wild-type petD mRNA to 156 to 166 bp downstream of the 5' end. Thus, the deletion extends into the putative promoter and 5' untranslated region of petD. No petD mRNA of the normal size can be detected in FUD6 cells, but a low level of a dicistronic message accumulates, which contains the coding regions for subunit IV and cytochrome f, the product of the upstream petA gene. petD transcriptional activity in FUD6 is not significantly altered from the wild-type level. This transcriptional activity was eliminated by petA promoter disruptions, suggesting that it originates at the petA promoter. We conclude that the petD-coding portion of most cotranscripts is rapidly degraded in FUD6, possibly following processing events that generate the 3' end of petA mRNA. A chloroplast transformant was constructed in which only the sequence from -81 to -2 relative to the major 5' end of the petD transcript was deleted. Although this deletion eliminates all detectable petD promoter activity, the transformant grows phototrophically and accumulates high levels of monocistronic petD mRNA. We conclude that the petD gene can be transcribed by functionally redundant promoters. In the absence of a functional petD promoter, a lack of transcription termination allows the downstream petD gene to be cotranscribed with the petA coding region and thereby expressed efficiently.

scholarly journals Loss of H2A.Z Is Not Sufficient to Determine Transcriptional Activity of Snf2-Related CBP Activator Protein or p400 Complexes

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Tamara A. Bowman ◽  
Madeline M. Wong ◽  
Linda K. Cox ◽  
Joseph J. Baldassare ◽  
John C. Chrivia
Keyword(s):  
Transcriptional Activity ◽  
Protein Complexes ◽  
Regulation Of Transcription ◽  
Wild Type ◽  
Transcript Levels ◽  
Activator Protein ◽  
Nucleosome Density

The p400 and SRCAP (Snf2-related CBP activator protein) complexes remodel chromatin by catalyzing deposition of histone H2A.Z into nucleosomes. This remodeling activity has been proposed as a basis for regulation of transcription by these complexes. Transcript levels ofp21orSp1mRNAs after knockdown of p400 or SRCAP reveals that each regulates transcription of these promoters differently. In this study, we asked whether deposition of H2A.Z within specific nucleosomes by p400 or SRCAP dictates transcriptional activity. Our data indicates that nucleosome density at specificp21orSp1promoter positions is not altered by the loss of either remodeling complex. However, knockdown of SRCAP or p400 reduces deposition of H2A.Z∼50% into allp21andSp1promoter nucleosomes. Thus, H2A.Z deposition is not targeted to specific nucleosomes. These results indicate that the deposition of H2A.Z by the p400 or SRCAP complexes is not sufficient to determine how each regulates transcription. This conclusion is further supported by studies that demonstrate a SRCAPΔATPmutant unable to deposit H2A.Z has similar transcriptional activity as wild-type SRCAP.

scholarly journals TATA-Binding Protein–TATA Interaction Is a Key Determinant of Differential Transcription of Silkworm Constitutive and Silk Gland-Specific tRNAAla Genes

2000 ◽  
Vol 20 (4) ◽  
pp. 1329-1343 ◽  
Author(s):  
Ching Ouyang ◽  
M. Juanita Martinez ◽  
Lisa S. Young ◽  
Karen U. Sprague
Keyword(s):  
Promoter Activity ◽  
Transcriptional Activity ◽  
Binding Protein ◽  
Tata Binding Protein ◽  
Silk Gland ◽  
Wild Type ◽  
Heparin Resistance ◽  
Transcription Complexes ◽  
Differential Transcription

ABSTRACT We have investigated the contribution of specific TATA-binding protein (TBP)–TATA interactions to the promoter activity of a constitutively expressed silkworm tRNAC Ala gene and have also asked whether the lack of similar interactions accounts for the low promoter activity of a silk gland-specific tRNASG Ala gene. We compared TBP binding, TFIIIB-promoter complex stability (measured by heparin resistance), and in vitro transcriptional activity in a series of mutant tRNAC Ala promoters and found that specific TBP-TATA contacts are important for TFIIIB-promoter interaction and for transcriptional activity. Although the wild-type tRNAC Ala promoter contains two functional TBP binding sequences that overlap, the tRNASG Ala promoter lacks any TBP binding site in the corresponding region. This feature appears to account for the inefficiency of the tRNASG Alapromoter since provision of either of the wild-type TATA sequences derived from the tRNAC Ala promoter confers robust transcriptional activity. Transcriptional impairment of the wild-type tRNASG Ala gene is not due to reduced incorporation of TBP into transcription complexes since both the tRNAC Ala and tRNASG Ala promoters form transcription complexes that contain the same amount of TBP. Thus, the deleterious consequences of the lack of appropriate TBP-TATA contacts in the tRNASG Ala promoter must come from failure to incorporate some other essential transcription factor(s) or to stabilize the complete complex in an active conformation.

scholarly journals Age-dependent changes in transcription factor FOXO targeting in Drosophila melanogaster

2018 ◽  
Author(s):  
Allison Birnbaum ◽  
Xiaofen Wu ◽  
Marc Tatar ◽  
Nan Liu ◽  
Hua Bai
Keyword(s):  
Drosophila Melanogaster ◽  
Transcriptional Activity ◽  
Normal Aging ◽  
Binding Activity ◽  
Nucleosome Assembly ◽  
Wild Type ◽  
Cellular Processes ◽  
Age Dependent ◽  
Chromatin Immunoprecipitation Sequencing ◽  
Foxo Transcription Factors

SummaryFOXO transcription factors have long been associated with longevity control and tissue homeostasis. Although the transcriptional regulation of FOXO have been previously characterized (especially in long-lived insulin mutants and under stress conditions), how normal aging impacts the transcriptional activity of FOXO is poorly understood. Here, we conducted a chromatin immunoprecipitation sequencing (ChIP-Seq) analysis in both young and old wild-type fruit flies, Drosophila melanogaster, to evaluate the dynamics of FOXO gene targeting during aging. Intriguingly, the number of FOXO-bound genes dramatically decreases with age (from 2617 to 224). Consistent to the reduction of FOXO binding activity, many genes targeted by FOXO in young flies are transcriptionally altered with age, either up-regulated (FOXO-repressing genes) or down-regulated (FOXO-activating genes). In addition, we show that many FOXO-bound genes in wild-type flies are unique from those in insulin receptor substrate chico mutants. Distinct from chico mutants, FOXO targets specific cellular processes (e.g., actin cytoskeleton) and signaling pathways (e.g., Hippo, MAPK) in young wild-type flies. FOXO targeting on these pathways decreases with age. Interestingly, FOXO targets in old flies are enriched in cellular processes like chromatin organization and nucleosome assembly. Furthermore, FOXO binding to core histone genes is well maintained at aged flies. Together, our findings provide new insights into dynamic FOXO targeting under normal aging and highlight the diverse and understudied regulatory mechanisms for FOXO transcriptional activity.

scholarly journals A genetic analysis of the Suppressor 2 of zeste complex of Drosophila melanogaster.

Genetics ◽  
1995 ◽  
Vol 140 (1) ◽  
pp. 139-181 ◽  
Author(s):  
C T Wu ◽  
M Howe
Keyword(s):  
Drosophila Melanogaster ◽  
Position Effect ◽  
Molecular Data ◽  
Polycomb Group ◽  
Position Effect Variegation ◽  
Wild Type ◽  
Trithorax Group ◽  
Eye Color ◽  
Multidomain Structure ◽  
Sex Combs

Abstract The zeste1 (z1) mutation of Drosophila melanogaster produces a mutant yellow eye color instead of the wild-type red. Genetic and molecular data suggest that z1 achieves this change by altering expression of the wild-type white gene in a manner that exhibits transvection effects. There exist suppressor and enhancer mutations that modify the z1 eye color, and this paper summarizes our studies of those belonging to the Suppressor 2 of zeste complex [Su(z)2-C]. The Su(z)2-C consists of at least three subregions called Psc (Posterior sex combs), Su(z)2 and Su(z)2D (Distal). The products of these subregions are proposed to act at the level of chromatin. Complementation analyses predict that the products are functionally similar and interacting. The alleles of Psc define two overlapping phenotypic classes, the hopeful and hapless. The distinctions between these two classes and the intragenic complementation seen among some of the Psc alleles are consistent with a multidomain structure for the product of Psc. Psc is a member of the homeotic Polycomb group of genes. A general discussion of the Polycomb and trithorax group of genes, position-effect variegation, transvection, chromosome pairing and chromatin structure is presented.

The petD gene is transcribed by functionally redundant promoters in Chlamydomonas reinhardtii chloroplasts

1994 ◽  
Vol 14 (9) ◽  
pp. 6171-6179
Author(s):  
N R Sturm ◽  
R Kuras ◽  
S Büschlen ◽  
W Sakamoto ◽  
K L Kindle ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Promoter Activity ◽  
Transcriptional Activity ◽  
Transcription Termination ◽  
Cytochrome F ◽  
Direct Repeats ◽  
Wild Type ◽  
Coding Region ◽  
Putative Promoter ◽  
Coding Regions

FUD6, a nonphotosynthetic mutant of Chlamydomonas reinhardtii, was previously found to be deficient in the synthesis of subunit IV of the cytochrome b6/f complex, the chloroplast petD gene product (C. Lemaire, J. Girard-Bascou, F.-A. Wollman, and P. Bennoun, Biochim. Biophys. Acta 851:229-238, 1986). The lesion in FUD6 is a 236-bp deletion between two 11-bp direct repeats in the chloroplast genome. It extends from 82 to 72 bp upstream of the 5' end of wild-type petD mRNA to 156 to 166 bp downstream of the 5' end. Thus, the deletion extends into the putative promoter and 5' untranslated region of petD. No petD mRNA of the normal size can be detected in FUD6 cells, but a low level of a dicistronic message accumulates, which contains the coding regions for subunit IV and cytochrome f, the product of the upstream petA gene. petD transcriptional activity in FUD6 is not significantly altered from the wild-type level. This transcriptional activity was eliminated by petA promoter disruptions, suggesting that it originates at the petA promoter. We conclude that the petD-coding portion of most cotranscripts is rapidly degraded in FUD6, possibly following processing events that generate the 3' end of petA mRNA. A chloroplast transformant was constructed in which only the sequence from -81 to -2 relative to the major 5' end of the petD transcript was deleted. Although this deletion eliminates all detectable petD promoter activity, the transformant grows phototrophically and accumulates high levels of monocistronic petD mRNA. We conclude that the petD gene can be transcribed by functionally redundant promoters. In the absence of a functional petD promoter, a lack of transcription termination allows the downstream petD gene to be cotranscribed with the petA coding region and thereby expressed efficiently.

scholarly journals The effect of modifiers of position-effect variegation on the variegation of heterochromatic genes of Drosophila melanogaster.

Genetics ◽  
1991 ◽  
Vol 128 (4) ◽  
pp. 785-797 ◽  
Author(s):  
M G Hearn ◽  
A Hedrick ◽  
T A Grigliatti ◽  
B T Wakimoto
Keyword(s):  
Drosophila Melanogaster ◽  
Position Effect ◽  
Position Effect Variegation ◽  
Chromosome 2 ◽  
Wild Type ◽  
Regulatory Requirements ◽  
Expression Of Genes ◽  
Effect Variegation ◽  
Type Gene ◽  
Heterochromatic Genes

Abstract Dominant modifiers of position-effect variegation of Drosophila melanogaster were tested for their effects on the variegation of genes normally located in heterochromatin. These modifiers were previously isolated as strong suppressors of the variegation of euchromatic genes and have been postulated to encode structural components of heterochromatin or other products that influence chromosome condensation. While eight of the modifiers had weak or no detectable effects, six acted as enhancers of light (lt) variegation. The two modifiers with the strongest effects on lt were shown to also enhance the variegation of neighboring heterochromatic genes. These results suggest that the wild-type gene products of some modifiers of position-effect variegation are required for proper expression of genes normally located within or near the heterochromatin of chromosome 2. We conclude that these heterochromatic genes have fundamentally different regulatory requirements compared to those typical of euchromatic genes.

scholarly journals The hobo Transposable Element Excises and Has Related Elements in Tephritid Species

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1339-1347
Author(s):  
Alfred M Handler ◽  
Sheilachu P Gomez
Keyword(s):  
Drosophila Melanogaster ◽  
Ceratitis Capitata ◽  
Bactrocera Dorsalis ◽  
Parsimony Analysis ◽  
Wild Type ◽  
Anastrepha Suspensa ◽  
Tephritid Species ◽  
Mutant Strains ◽  
Almost All ◽  
Horizontal Transfers

Abstract Function of the Drosophila melanogaster hobo transposon in tephritid species was tested in transient embryonic excision assays. Wild-type and mutant strains of Anastrepha suspensa, Bactrocera dorsalis, B. cucurbitae, Ceratitis capitata, and Toxotrypana curvicauda all supported hobo excision or deletion both in the presence and absence of co-injected hobo transposase, indicating a permissive state for hobo mobility and the existence of endogenous systems capable of mobilizing hobo. In several strains hobo helper reduced excision. Excision depended on hobo sequences in the indicator plasmid, though almost all excisions were imprecise and the mobilizing systems appear mechanistically different from hobo. hobe-related sequences were identified in all species except T. curvicauda. Parsimony analysis yielded a subgroup including the B. cucurbitae and C. capitata sequences along with hobo and Hermes, and a separate, more divergent subgroup including the A. suspensa and B. dorsalis sequences. All of the sequences exist as multiple genomic elements, and a deleted form of the B. cucurbitae element exists in B. dorsalis. The hobo-related sequences are probably members of the hAT transposon family with some evolving from distant ancestor elements, while others may have originated from more recent horizontal transfers.

scholarly journals Production and scavenging of reactive oxygen species both affect reproductive success in male and female Drosophila melanogaster

2021 ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Klaus Reinhardt
Keyword(s):  
Reactive Oxygen Species ◽  
Drosophila Melanogaster ◽  
Reactive Oxygen ◽  
Cellular Aging ◽  
Ros Production ◽  
Oxygen Species ◽  
Wild Type ◽  
Ros Scavenging ◽  
Respiratory Pathway ◽  
Male And Female

AbstractSperm aging is accelerated by the buildup of reactive oxygen species (ROS), which cause oxidative damage to various cellular components. Aging can be slowed by limiting the production of mitochondrial ROS and by increasing the production of antioxidants, both of which can be generated in the sperm cell itself or in the surrounding somatic tissues of the male and female reproductive tracts. However, few studies have compared the separate contributions of ROS production and ROS scavenging to sperm aging, or to cellular aging in general. We measured reproductive fitness in two lines of Drosophila melanogaster genetically engineered to (1) produce fewer ROS via expression of alternative oxidase (AOX), an alternative respiratory pathway; or (2) scavenge fewer ROS due to a loss-of-function mutation in the antioxidant gene dj-1β. Wild-type females mated to AOX males had increased fecundity and longer fertility durations, consistent with slower aging in AOX sperm. Contrary to expectations, fitness was not reduced in wild-type females mated to dj-1β males. Fecundity and fertility duration were increased in AOX and decreased in dj-1β females, indicating that female ROS levels may affect aging rates in stored sperm and/or eggs. Finally, we found evidence that accelerated aging in dj-1β sperm may have selected for more frequent mating. Our results help to clarify the relative roles of ROS production and ROS scavenging in the male and female reproductive systems.

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