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PubMed1993

Drosophila tyrosine hydroxylase is encoded by the pale locus.

We have reintroduced an 8 kb genomic fragment from the Drosophila tyrosine hydroxylase (DTH) locus into the genome of mutant pale (ple) flies. ple was first recovered as a recessive embryonic lethal by Jurgens et al. (1984) and maps to the same chromosomal region as DTH (65A-E). Mutant ple alleles affect pigmentation of the cuticle (L-DOPA, the product of the reaction catalyzed by TH, is an intermediate in the cuticular sclerotization and pigmentation pathways) and catecholamine biosynthesis. In this report we demonstrate that ple does encode the structural gene for TH, since the reintroduced sequences rescue ple flies from lethality to viable adults. Morphological, immunocytochemical, and behavioral characterization of three transformant lines suggests that the reintroduced sequences contain the necessary elements for correct temporal and spatial expression of the gene, but may not contain all the sequences essential for quantitative expression.

Animals↗
PubMed2005

Heat shock, histone H3 phosphorylation and the cell cycle.

Genome-wide and gene-specific changes in histone H3 phosphorylation during heat shock have recently been described using two well-established experimental models, the "puffing" of heat shock loci in Drosophila polytene chromosomes and the induction of hsp70 mRNA transcripts in cultured mouse cells. Despite conservation of the molecular participants and overall stress response in these two organisms, some striking differences have emerged. Here, we summarize accounts of heat shock-modulated histone phosphorylation in Drosophila and mouse cells highlighting these differences. In addition, we describe a further complexity of this response in cultured mouse cells that becomes apparent when the nucleosomal response, referring to histone H3 and HMGN1 phosphorylation, is monitored through the cell cycle. This suggests that some heat shock-induced effects in mouse cells may be indirect and arise as a secondary consequence of the effect of heat shock on the cell cycle, complicating comparisons between the fly and mouse systems.

Animals↗
PubMed1999

Interbands of Drosophila melanogaster polytene chromosomes contain matrix association regions.

The DNA of three previously cloned interband regions (85D9/D10, 86B4/B6, and 61C7/C8) of Drosophila melanogaster polytene chromosomes has been tested for the presence of matrix association regions (MAR), using the in vitro matrix-binding assay of Cockerill and Garrard. MARs were found in all three interband regions under study. These results are discussed in frames of a model postulating that interband regions of polytene chromosomes correspond to the chromosomal DNA loop borders, which can be identified in interphase nuclei using biochemical approaches.

Animals↗
PubMed2000

Novel mechanism of massive photoreceptor degeneration caused by mutations in the trp gene of Drosophila.

The Drosophila trp gene encodes a light-activated Ca(2+) channel subunit, which is a prototypical member of a novel class of channel proteins. Previously identified trp mutants are all recessive, loss-of-function mutants characterized by a transient receptor potential and the total or near-total loss of functional TRP protein. Although retinal degeneration does occur in these mutants, it is relatively mild and slow in onset. We report herein a new mutant, Trp(P365), that does not display the transient receptor potential phenotype and is characterized by a substantial level of the TRP protein and rapid, semi-dominant degeneration of photoreceptors. We show that, in spite of its unusual phenotypes, Trp(P365) is a trp allele because a Trp(P365) transgene induces the mutant phenotype in a wild-type background, and a wild-type trp transgene in a Trp(P365) background suppresses the mutant phenotype. Moreover, amino acid alterations that could cause the Trp(P365) phenotype are found in the transmembrane segment region of the mutant channel protein. Whole-cell recordings clarified the mechanism underlying the retinal degeneration by showing that the TRP channels of Trp(P365) are constitutively active. Although several genes, when mutated, have been shown to cause retinal degeneration in Drosophila, the underlying mechanism has not been identified for any of them. The present studies provide evidence for a specific mechanism for massive degeneration of photoreceptors in Drosophila. Insofar as some human homologs of TRP are highly expressed in the brain, a similar mechanism could be a major contributor to degenerative disorders of the brain.

Amino Acid Sequence↗
PubMed1975

[Cytochemical study of the elimination chromatin in silkworm meiosis].

The elimination chromatin separating from chromosomes during the first maturation division of female sex cells of lepidoptera insects was studied cytochemically on paraffin sections of eggs of Bombyx mori L. Ocytes at the metaphase-telophase stage of the first meiotic division were stained for RNA by metyl green-pyronin and gallocyanin with negative results. These data differ from earlier positive results for Solenobia triquetrella reported by Ris and Kleinfeld, 1952.

Animals↗
PubMedDate not supplied

[Malaria mosquitoes in Moscow and in the Moscow Region: cytogenetic analysis].

The species and karyotypical composition of malaria mosquitoes in Moscow and in the Moscow Region have been examined. A cytogenetic analysis in the Moscow Region has revealed 3 types of malaria mosquitoes: Anopheles claviger Mg., An. maculipennis Mg., and An. messeae Fall. An. messeae predominates in the Solnechnogorsk and Noginsk Regions, An. maculipennis prevails in the Ramensk and Serpukhov Regions. In the combined habitats, the ratio of two predominant types has been ascertained to vary during a season. The proportion of An. maculipennis increases by the end of summer and decreases during hibernation. The more northern type of An. messeae has been shown to be superior to An. maculipennis in fertility. Thus, the increased relative size of An. maculipennis during summer is due to the higher viability of the larvae of this type. In the Moscow water reservoirs, the larvae of both types develop concurrently; the proportion of An. messeae is 89.8%. The high level of chromosomal variability was found in the urban populations of An. messeae by the inversions of XL1, XL3, 2R1, 3R1. A role of chromosomal variability in the adaptation of mosquitoes to urban conditions is discussed.

Animals↗
PubMed1992

[Properties of super unstable mutations in the Drosophila melanogaster yellow locus].

The properties of super-unstable systems of the white, singed and ocetilless loci obtained as a result of P-M dysgenesis induction in the strains with a mobilized Stalker were described earlier. In the studies of super-instability in ocetilless locus, six super-unstable mutations in the yellow locus were obtained. Detailed genetic analysis was performed resulting in isolation of 80 alleles with different phenotype expression. In general, super-instability in the yellow locus reminds that in the white and ocetilless loci. Most of alleles are highly unstable possessing a characteristic pattern of mutation changes. Also, sub-systems were found in the yellow super-unstable system. Each consists of several mutually inter-converting alleles which possess a characteristic phenotype, mode and rate of mutation changes.

Alleles↗
PubMed1990

A genetic study of the malaria vector Anopheles nuneztovari from western Venezuela.

A photomap of larval polytene chromosomes of Anopheles nuneztovari (population B) from western Venezuela is presented. Samples of An. nuneztovari B taken from 4 study sites in the states of Barinas and Táchira comprise a single panmictic population, which is chromosomally identical to the cytotype identified by Kitzmiller et al. (1973) from western Venezuela and Colombia. The frequency of polymorphism 2La has increased significantly in the 16 years that have elapsed since the 1973 study. In addition, inversion 2La does not conform to Hardy-Weinberg equilibrium. These 2 changes are most likely due to environmental alterations which have resulted in the heterozygous condition becoming more locally adaptive.

Animals↗
PubMed1989

Field studies on inversion polymorphism in Anopheles superpictus from southern Italy.

Polytene chromosome studies were carried out on various population samples of Anopheles superpictus from different localities in Southern Italy. More than 7,000 female specimens, mostly obtained from daytime collections of indoor resting mosquitoes, were successfully scored for nurse cell polytene chromosomes. Night biting samples were also examined in some localities. Only one chromosomal polymorphism, due to a paracentric inversion involving the central third of the 2L arm, was recorded in all samples. In all localities, the inverted 2La arrangement showed remarkably stable frequency although the populations examined were isolated from each other and at least some of them have presumably been subject to bottle neck in recent years because of insecticide treatments or ecological changes affecting the availability of breeding places. Departures from the Hardy-Weinberg expectations, indicating an excess of heterokaryotypes, were noted and critically analysed by comparing samples obtained simultaneously in the same locality from different cow sheds, from different sections of the same cow shed and from night and day catches in the same cow shed. The phenomenon was not found uniformly distributed among indoor resting samples: significant departures from the Hardy-Weinberg expectations were observed in some cow sheds but not in others situated nearby or even adjacent to them. These results did not support the hypothesis that the excess of heterokaryotypes is due to their greater longevity or to differential mortality in the preimaginal stages. It is suggested that different karyotypes may react differently to microclimatic specific conditions, since the Hardy-Weinberg disequilibrium was mostly observed in samples from resting sites that were more lit and subject to wider climatic variation.

Animals↗
PubMed1984

[Radiation-induced inversions and reciprocal translocations in Anopheles atroparvus].

Inversions and reciprocal translocations were induced in Anopheles atroparvus by irradiation of males with X-rays. 22 aberrations were produced in stocks and were identified as follows: 6 paracentric, 6 pericentric inversions and 10 reciprocal translocations (9 autosomal and 1 sex-linked). Partial sterility in the offspring of this stock is demonstrated. The practical significance of constructing stocks with inversions and translocations for genetic control of pest insects is considered.

Animals↗
PubMed1993

A repetitive secretory protein gene of a novel type in Chironomus tentans is specifically expressed in the salivary glands and exhibits extensive length polymorphism.

The secretion from the salivary glands in the dipteran Chironomus tentans has previously been shown to contain secretory proteins encoded by a set of related genes belonging to the Balbiani ring multigene family. Here we describe the characterization of a gene for an additional secretory protein of a novel type. This sp240/420 gene is built from virtually identical 477-base pair repeats organized in tandem. The gene exhibits extensive length polymorphism since allelic length variants with from 12 to 22 repeats were recorded. Antibodies have been raised against the gene product, and it is shown also that the protein varies in size between 240 and 420 kDa. The protein is rich in serine and threonine residues (30%) and has N-linked carbohydrate chains, presumably on each repeat. Despite careful preparation of the gland lumen proteins, the sp240/420 protein was found to form protein ladders of regularly degraded protein, suggesting that this degradation occurs naturally in the salivary glands. Although all previously characterized salivary gland secretory protein genes in C. tentans belong to the same multigene family, the sp240/420 gene appears to represent a novel, unrelated type of repetitive gene. The chromosomal location of the gene was mapped and was found to reside in region 17 on chromosome I.

Amino Acid Sequence↗
PubMed1994

Localization of the Cu/Zn superoxide dismutase gene in the Drosophila willistoni species group by in situ hybridization.

Due to the physiological importance of its product, the Cu/Zn superoxide dismutase enzyme, the gene coding for this enzyme was mapped in five species of the Drosophila willistoni subgroup and in D. nebulosa by in situ hybridization using D. melanogaster as a control. The results indicate that this locus is located on the XR chromosomal arm of the five sibling species and on the XL chromosomal arm of D. nebulosa, suggesting the occurrence of a pericentric inversion before the separation of these entities.

Animals↗
PubMed1997

[Interaction of mutations of the genes for mutagen sensitivity mei-9, mei-41 and rad201 as affected by ionizing radiation].

Double mutants mei-41D5; rad(2)201G1 and mei-9a; rad(2)201G1 were constructed to study the interaction of these mutations in Drosophila exposed to gamma-rays. mei-9 and mei-41 mutants are sensitive to the lethal effects of a broad spectrum of chemical and physical factors, while rad201 mutants are sensitive only to ionizing radiation. The results obtained showed that the interaction of mei-9 and rad201 mutations is additive and the interaction of mei-41 and rad201 mutations is epistatic. The maternal effect was demonstrated to be characteristic of all mutants tested even when larvae were exposed to radiation at a late stage of development.

Animals↗
PubMedDate not supplied

[The Delta locus in Drosophila virilis: alleles, wing phenotypes and genetic interactions].

A considerable number of Delta (D1) alleles resulting from spontaneous mutation or induced by following X-ray irradiation have been isolated on the basis of the dominant phenotype consisting of disrupted wing venation and associated with heterozygosity for different D1 alleles. The L2 "delta" forming at the wing margin is the most characteristic fully penetrant phenotype of D1-heterozygous adults. The structure disruption of all other longitudinal (L3-L5) and cross (C1 and C2) veins including formation of "deltas" and other additional vein material, have been characterized as the irregular bilaterally asymmetrical nondirectional fluctuations of D1 phenotype expression. The phenotypic interactions between Delta and two D1 phenotype enhancer mutations, L2 fork and gap L2, have been found. Possible participation of Delta, one of the elements of Notch signaling system, in the structure formation is discussed.

Alleles↗