Structure and expression of hybrid dysgenesis-induced alleles of the ovarian tumor (otu) gene in Drosophila melanogaster.

Abstract Mutations at the ovarian tumor (otu) gene of Drosophila melanogaster cause female sterility and generate a range of ovarian phenotypes. Quiescent (QUI) mutants exhibit reduced germ cell proliferation; in oncogenic (ONC) mutants germ cells undergo uncontrolled proliferation generating excessive numbers of undifferentiated cells; the egg chambers of differentiated (DIF) mutants differentiate to variable degrees but fail to complete oogenesis. We have examined mutations caused by insertion and deletion of P elements at the otu gene. The P element insertion sites are upstream of the major otu transcription start sites. In deletion derivatives, the P element, regulatory regions and/or protein coding sequences have been removed. In both insertion and deletion mutants, the level of otu expression correlates directly with the severity of the phenotype: the absence of otu function produces the most severe QUI phenotype while the ONC mutants express lower levels of otu than those which are DIF. The results of this study demonstrate that the diverse mutant phenotypes of otu are the consequence of different levels of otu function.

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Cytoplasmic dynein (ddlc1) mutations cause morphogenetic defects and apoptotic cell death in Drosophila melanogaster.

Molecular and Cellular Biology ◽

10.1128/mcb.16.5.1966 ◽

1996 ◽

Vol 16 (5) ◽

pp. 1966-1977 ◽

Cited By ~ 104

Author(s):

T Dick ◽

K Ray ◽

H K Salz ◽

W Chia

Keyword(s):

Drosophila Melanogaster ◽

Light Chain ◽

Blot Analysis ◽

Cytoplasmic Dynein ◽

P Element ◽

Female Sterility ◽

Dynein Light Chain ◽

Loss Of Function ◽

Light Chain Gene

We report the molecular and genetic characterization of the cytoplasmic dynein light-chain gene, ddlc1, from Drosophila melanogaster. ddlc1 encodes the first cytoplasmic dynein light chain identified, and its genetic analysis represents the first in vivo characterization of cytoplasmic dynein function in higher eucaryotes. The ddlc1 gene maps to 4E1-2 and encodes an 89-amino-acid polypeptide with a high similarity to the axonemal 8-kDa outer-arm dynein light chain from Chlamydomonas flagella. Developmental Northern (RNA) blot analysis and ovary and embryo RNA in situ hybridizations indicate that the ddlc1 gene is expressed ubiquitously. Anti-DDLC1 antibody analyses show that the DDLC1 protein is localized in the cytoplasm. P-element-induced partial-loss-of-function mutations cause pleiotropic morphogenetic defects in bristle and wing development, as well as in oogenesis, and hence result in female sterility. The morphological abnormalities found in the ovaries are always associated with a loss of cellular shape and structure, as visualized by a disorganization of the actin cytoskeleton. Total-loss-of-function mutations cause lethality. A large proportion of mutant animals degenerate during embryogenesis, and the dying cells show morphological changes characteristic of apoptosis, namely, cell and nuclear condensation and fragmentation, as well as DNA degradation. Cloning of the human homolog of the ddlc1 gene, hdlc1, demonstrates that the dynein light-chain 1 is highly conserved in flies and humans. Northern blot analysis and epitope tagging show that the hdlc1 gene is ubiquitously expressed and that the human dynein light chain 1 is localized in the cytoplasm. hdlc1 maps to 14q24.

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Molecular organization and expression of the genetic locus glued in Drosophila melanogaster

Molecular and Cellular Biology ◽

10.1128/mcb.6.3.833-841.1986 ◽

1986 ◽

Vol 6 (3) ◽

pp. 833-841

Author(s):

A Swaroop ◽

J W Sun ◽

M L Paco-Larson ◽

A Garen

Keyword(s):

Drosophila Melanogaster ◽

Cell Function ◽

Genetic Locus ◽

Insertion Site ◽

Lethal Effect ◽

P Element ◽

Molecular Organization ◽

General Distribution ◽

Element Insertion ◽

Mutant Phenotypes

The Glued locus of Drosophila melanogaster is genetically defined as the functional unit which is affected by the dominant Glued mutation Gl. Genomic DNA was cloned from the region of the Glued locus, at 70C2 on chromosome 3, by using a P element insertion in the region as a molecular marker. Three genes encoding polyadenylated transcripts were detected within a 30-kilobase span of the cloned DNA. The gene nearest the P element insertion site was identified as a Glued gene on the basis of alterations in its DNA and encoded transcript associated with the Gl mutation and with reversions of Gl which eliminate the dominant effect by inactivation of the mutant allele. Expression of the wild-type Gl+ gene is temporally regulated during development; the amount of the encoded transcript is highest in the embryonic stage, decreasing in the first and second larval instars, and then increasing in the third instar and pupal stages. There is a maternal contribution of the Gl+ transcript to the embryo, which probably accounts for the maternal lethal effect of Glued mutations on early development. In situ hybridizations of Gl+ DNA to RNA in tissue sections showed that the Gl+ transcript is present in virtually all tissues of the embryo, late larva, and pupa. The general distribution of this transcript is consistent with genetic evidence indicating that the Glued locus controls a generally essential cell function (P. J. Harte and D. R. Kankel, Genetics 101:477-501, 1982). Different Glued mutations produce distinct phenotypic effects, including adults with severe visual defects, larvae lacking imaginal discs, and early lethality. These diverse mutant phenotypes are discussed in terms of quantitative changes in the Glued function. Closely adjacent to Gl+ is another gene which is transcribed in a divergent direction and expressed coordinately with Gl+ throughout Drosophila development. It remains to be determined whether this gene is also involved with the Glued function.

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Studies on the female-sterile phenotype of 1(1)su(f) ts76a, a temperature-sensitive allele of the suppressor of forked mutation in Drosophila melanogaster

Development ◽

10.1242/dev.55.1.247 ◽

1980 ◽

Vol 55 (1) ◽

pp. 247-256

Author(s):

Thomas G. Wilson

Keyword(s):

Cell Death ◽

Drosophila Melanogaster ◽

Follicle Cell ◽

Lethal Mutation ◽

Female Sterility ◽

Temperature Sensitive ◽

Egg Chambers ◽

A Cell ◽

Sensitive Allele

A new allele of the suppressor of forked [su(f)] mutation in Drosophila melanogaster has been found and designated 1(1)su(f)ts76a. It is temperature-sensitive for suppression of forked (f) and has additional temperature-sensitive phenotypes of lethality, female sterility, and abnormal bristle formation at 29 °C. It closely resembles two other conditional alleles of su(f), 1(1)su(f)ts67g and 1(1)ts726. Female sterility at 29 °C is characterized by both disorganized egg chambers in the ovarioles and also chorion-deficient oocytes. Both of these abnormalities may be the result of premature follicle cell death. The observations on 1(1)su(f)ts76a are consistent with the proposal that the similar allele, 1(1)ts726, is a cell-lethal mutation specifically affecting mitotically active cells.

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Construction, stable transformation, and function of an amber suppressor tRNA gene in Drosophila melanogaster

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.86.17.6696 ◽

1989 ◽

Vol 86 (17) ◽

pp. 6696-6698 ◽

Cited By ~ 19

Author(s):

F A Laski ◽

S Ganguly ◽

P A Sharp ◽

U L RajBhandary ◽

G M Rubin

Keyword(s):

Drosophila Melanogaster ◽

Trna Gene ◽

P Element ◽

Female Sterility ◽

Suppressor Trna ◽

Amber Codon ◽

Amber Suppressor ◽

Chloramphenicol Acetyltransferase Gene ◽

Male And Female Sterility ◽

And Function

Drosophila melanogaster strains with a stably incorporated amber suppressor tRNA gene have been generated. A tRNATyr gene was site specifically mutated to produce an anticodon sequence that recognizes the amber codon and then introduced into Drosophila by using P-element-mediated transformation. Transformants from four integration events were recovered. Two integrations resulted in both male and female sterility, whereas the other two resulted in male sterility but female fertility. Strains derived from the two female-fertile integration events were shown to have a low level of amber-suppressing activity by their ability to suppress an amber mutation in a chloramphenicol acetyltransferase gene.

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P-element-induced control mutations at the r gene of Drosophila melanogaster.

Molecular and Cellular Biology ◽

10.1128/mcb.5.10.2567 ◽

1985 ◽

Vol 5 (10) ◽

pp. 2567-2574 ◽

Cited By ~ 25

Author(s):

S Tsubota ◽

M Ashburner ◽

P Schedl

Keyword(s):

Drosophila Melanogaster ◽

The Other ◽

P Element ◽

Female Sterility ◽

R Gene ◽

Temporal Expression ◽

Base Pairs ◽

P Elements ◽

Adult Females ◽

Regulatory Mutations

The P-M hybrid dysgenesis system was used to produce five putative regulatory mutations at the rudimentary locus, r. All five mutations were the result of insertions at the 5' end of the gene, upstream of the proposed start of transcription. All of the mutants displayed a leaky wing phenotype, and four of the mutants showed an uncoupling of the wing and female-sterility phenotypes, suggesting that they altered the normal spatial and temporal expression of the r gene. Four of the insertions were P elements. The fifth insertion, which was larger than an intact P element, consisted of a small P element connected to non-P-element DNA. Two of the mutants produced very little r transcript in adult females and were clustered 80 to 150 base pairs upstream of the start of transcription. The other three mutants had higher levels of r transcript in adult females and were clustered 440 to 500 base pairs upstream of the start of transcription. All of the data suggest that the insertions are in a 5' noncoding region of the r gene involved in the control of its spatial and temporal expression.

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An Exploration of the Sequence of a 2.9-Mb Region of the Genome of Drosophila melanogaster: The Adh Region

Genetics ◽

10.1093/genetics/153.1.179 ◽

1999 ◽

Vol 153 (1) ◽

pp. 179-219 ◽

Cited By ~ 15

Author(s):

M Ashburner ◽

S Misra ◽

J Roote ◽

S E Lewis ◽

R Blazej ◽

...

Keyword(s):

Drosophila Melanogaster ◽

Transposable Element ◽

Large Scale ◽

Chromosome Region ◽

Complete Sequence ◽

Test Methods ◽

P Element ◽

Cdna Libraries ◽

Protein Coding ◽

Protein Coding Genes

Abstract A contiguous sequence of nearly 3 Mb from the genome of Drosophila melanogaster has been sequenced from a series of overlapping P1 and BAC clones. This region covers 69 chromosome polytene bands on chromosome arm 2L, including the genetically well-characterized “Adh region.” A computational analysis of the sequence predicts 218 protein-coding genes, 11 tRNAs, and 17 transposable element sequences. At least 38 of the protein-coding genes are arranged in clusters of from 2 to 6 closely related genes, suggesting extensive tandem duplication. The gene density is one protein-coding gene every 13 kb; the transposable element density is one element every 171 kb. Of 73 genes in this region identified by genetic analysis, 49 have been located on the sequence; P-element insertions have been mapped to 43 genes. Ninety-five (44%) of the known and predicted genes match a Drosophila EST, and 144 (66%) have clear similarities to proteins in other organisms. Genes known to have mutant phenotypes are more likely to be represented in cDNA libraries, and far more likely to have products similar to proteins of other organisms, than are genes with no known mutant phenotype. Over 650 chromosome aberration breakpoints map to this chromosome region, and their nonrandom distribution on the genetic map reflects variation in gene spacing on the DNA. This is the first large-scale analysis of the genome of D. melanogaster at the sequence level. In addition to the direct results obtained, this analysis has allowed us to develop and test methods that will be needed to interpret the complete sequence of the genome of this species.

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fs (1) Yb is required for ovary follicle cell differentiation in Drosophila melanogaster and has genetic interactions with the Notch group of neurogenic genes.

Genetics ◽

10.1093/genetics/140.1.207 ◽

1995 ◽

Vol 140 (1) ◽

pp. 207-217 ◽

Cited By ~ 1

Author(s):

E Johnson ◽

S Wayne ◽

R Nagoshi

Keyword(s):

Cell Fate ◽

Ovarian Follicle ◽

Follicle Cell ◽

Follicle Cells ◽

Female Sterility ◽

Specific Factor ◽

Temperature Sensitive ◽

Egg Maturation ◽

Egg Chambers ◽

Mutant Phenotypes

Abstract Phenotypic and genetic analyses demonstrate that fs (1) Yb activity is required in the soma for the development of a subset of ovarian follicle cells and to support later stages of egg maturation. Mutations in fs (1) Yb cause a range of ovarian phenotypes, from the improper segregation of egg chambers to abnormal dorsal appendage formation. The mutant phenotypes associated with fs (1) Yb are very similar to the ovarian aberrations produced by temperature-sensitive alleles of Notch and Delta. Possible functional or regulatory interactions between fs (1) Yb and Notch are suggested by genetic studies. A duplication of the Notch locus partially suppresses the female-sterility caused by fs (1) Yb mutations, while reducing Notch dosage makes the fs (1) Yb mutant phenotype more severe. In addition, fs (1) Yb alleles also interact with genes that are known to act with or regulate Notch activity, including Delta, daughterless, and mastermind. However, differences between the mutant ovarian phenotype of fs (1) Yb and that of Notch or Delta indicate that the genes do not have completely overlapping functions in the ovary. We propose that fs (1) Yb acts as an ovary-specific factor that determines follicle cell fate.

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Molecular genetics of the Drosophila melanogaster ovo locus, a gene required for sex determination of germline cells.

Genetics ◽

10.1093/genetics/130.4.791 ◽

1992 ◽

Vol 130 (4) ◽

pp. 791-803

Author(s):

M D Garfinkel ◽

A R Lohe ◽

A P Mahowald

Keyword(s):

Drosophila Melanogaster ◽

Sex Determination ◽

Genomic Dna ◽

Transcription Unit ◽

Complementation Group ◽

P Element ◽

Female Sterility ◽

Germline Cells ◽

Female Specific ◽

Female Germline

Abstract The Drosophila melanogaster ovo gene is required for survival and differentiation of female germline cells, apparently playing a role in germline sex determination. We recovered 60 kb of genomic DNA from its genetic location at 4E1,2 on the X chromosome. A transcription unit coding for an apparently female-specific germline-dependent 5-kb poly(A)+ RNA size class is located substantially in a 7-kb region, within which three DNA-detectable lesions for mutations that inactivate the ovo function are located at two sites approximately 4 kb apart. The breakpoint of a deficiency that removes the neighboring lethal complementation group shavenbaby (svb) but leaves the ovo function intact maps approximately 5 kb to the molecular left of the leftmost ovo mutant site. A class of mutations that inactivates both the svb function and the ovo function affects genomic DNA between the two ovo sites. Sequences required for the two genetic functions are partly overlapping. In spite of this overlap, P element-mediated gene transfer of a 10-kb genomic DNA segment containing the 5-kb poly(A)+ RNA transcription unit rescues the female sterility phenotypes of ovo mutations, but not the svb lethality.

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TRANSPOSABLE ELEMENT-INDUCED RESPONSE TO ARTIFICIAL SELECTION IN DROSOPHILA MELANOGASTER

Genetics ◽

10.1093/genetics/111.2.351 ◽

1985 ◽

Vol 111 (2) ◽

pp. 351-374

Author(s):

Trudy F C Mackay

Keyword(s):

Drosophila Melanogaster ◽

Genetic Variation ◽

Artificial Selection ◽

Abdominal Tergite ◽

P Element ◽

Induced Response ◽

Phenotypic Variance ◽

P Elements ◽

Insertion And Deletion ◽

Multiple Copies

ABSTRACT The P family of transposable elements in Drosophila melanogaster transpose with exceptionally high frequency when males from P strains carrying multiple copies of these elements are crossed to females from M strains that lack P elements, but with substantially lower frequency in the reciprocal cross. Transposition is associated with enhanced mutation rates, caused by insertion and deletion of P elements, and chromosome rearrangements. If P element mutagenesis creates additional variation for quantitative traits, accelerated response to artificial selection of progeny of M♀♀ × P♂♂ strain crosses is expected, compared with that from progeny of P♀♀ × M♂♂ strain crosses.—Divergent artificial selection for number of bristles on the last abdominal tergite was carried out for 16 generations among the progeny of P–strain males (Harwich) and M–strain females (Canton-S) and also of M–strain males (Canton-S) and P-strain females (Harwich). Each cross was replicated four times. Average realized heritability of abdominal bristle score for the crosses in which P transposition was expected was 0.244 ± 0.017, 1.5 times greater than average heritability estimated from crosses in which transposition was expected to be rare (0.163 ± 0.010). Phenotypic variance of abdominal bristle score increased by a factor of four in lines selected from M♀♀ × P♂♂ crosses when compared with those selected from P♀♀ × M♂♂ hybrids. Not all quantitative genetic variation induced by P elements is additive. A substantial fraction of nonadditive genetic variation is implicated by chromosomal analysis, which demonstrates deleterious fitness effects of the mutations when homozygous.—Several putative "quantitative" mutations were identified from chromosomes extracted from the selected lines; these will form the basis for further investigation at the molecular level of the genes controlling quantitative inheritance.

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