A photographic study of development in the living embryo of Drosophila melanogaster

The changes which can be seen occurring during the development of a living embryo of Drosophila melanogaster are described in detail, and represented photographically as a series of developmental stages. This provides an easy, but accurate technique for selecting eggs at precise developmental stages for experiments.     

Localization of thoracic imaginal-disc precursor cells in the early embryo of Drosophila melanogaster

Our previous cell lineage analysis of the thoracic disc primordia of Drosophila showed that at the blastoderm and early gastrula stage, cells are not yet committed to form either larval or imaginal tissue (Meise and Janning, 1993). We have now refined our studies on the cell lineage and have mapped the imaginal primordia in the thoracic region. Homotopic transplantations of single cells within the thoracic region of blastoderm and early gastrula stages show that the precursor cells of thoracic imaginal discs are locally restricted to a small lateral area of the thoracic region. Clones labelling leg discs frequently included the Keilin's organs. Heterotopic transplantations along the dorsoventral axis indicate that cells within the thoracic region are not yet committed with respect to larval or imaginal tissue, their fate being dependent on the position where the transplanted cell had been deposited. On the other hand, cells taken from the abdominal anlagen and transplanted into the region of thoracic disc primordia could not participate in the formation of imaginal discs. This shows that, in contrast to the dorsoventral axis, determinative events had separated primordia along the anterior-posterior axis.     

New genes for male accessory gland proteins in Drosophila melanogaster

The accessory gland of male insects produces components of the seminal fluid that alter the behavior, physiology and life span of the mated female, and contribute to her efficient storage and utilization of sperm. As a step towards understanding how this occurs, we have isolated genes encoding 12 previously unreported accessory gland-specific mRNAs from the fruit fly Drosophila melanogaster. We report here the restriction maps of the new genes, the chromosome positions--which are all autosomal--of the 11 non-repetitive genes, their expression patterns, and the sequences of the accessory gland proteins (Acps) encoded by nine of the genes. Eight of the proteins predicted from these sequences begin with putative secretion signals. Following their signal sequences, three of the predicted molecules are peptides and the other five are larger polypeptides with characteristics of cleavable prohormones. The ninth molecule, which has an N-terminal hydrophobic region but no consensus signal peptide cleavage site, is predicted to be a 716 amino acid glycoprotein. Of the nine proteins, two have intriguing similarities to sequences in protein databases. Acp76A is a 388 amino acid pro-protein which contains a signature sequence for the serpin class of protease inhibitors. The 115 amino acid Acp62F has a 28 amino acid region of high sequence similarity to a neurotoxin of the Brazilian armed spider Phoneutria nigriventer. Models are discussed in which Acp76A plays a role in the observed regulation of Acp proteolysis and/or in the coagulation of seminal fluid to form a mating plug, and in which Acp62F contributes to the reported toxicity of Drosophila seminal fluid.     

Mutation "outbursts" of various genes in natural populations of Drosophila melanogaster

The evaluation and treatment of older men with benign prostatic hyperplasia (BPH) is complicated by the highly variable clinical presentation of men with BPH, which ranges from minor urinary symptoms to acute urinary retention. Treatment choices have expanded with recent advances in medical and surgical therapies. Surgical treatment includes open prostatectomy and transurethral prostatectomy as well as newer technologies that are less invasive and that result in fewer long-term side effects. Response to treatment depends on the patient and should be directed at symptom relief.     

Identification of genes controlling malpighian tubule and other epithelial morphogenesis in Drosophila melanogaster

The Drosophila Malpighian tubule is a model system for studying genetic mechanisms that control epithelial morphogenesis. From a screen of 1800 second chromosome lethal lines, by observing uric acid deposits in unfixed inviable embryos, we identified five previously described genes (barr, fas, flb, raw, and thr) and one novel gene, walrus (wal), that affect Malpighian tubule morphogenesis. Phenotypic analysis of these mutant embryos allows us to place these genes, along with other previously described genes, into a genetic pathway that controls Malpighian tubule development. Specifically, wal affects evagination of the Malpighian tubule buds, fas and thr affect bud extension, and barr, flb, raw, and thr affect tubule elongation. In addition, these genes were found to have different effects on development of other epithelial structures, such as foregut and hindgut morphogenesis. Finally, from the same screen, we identified a second novel gene, drumstick, that affects only foregut and hindgut morphogenesis.     

Programming the Drosophila embryo

A critical step in understanding the mechanisms of development is in defining the steps at the molecular, cellular, and organismal levels in the developmental program for a given organism-so that given the egg one can predict not only how the embryo will develop but also how that embryo evolved from its ancestors. Using methods employed by chemists and engineers in modeling hierarchical systems, I have integrated current theory and experiment into a calculational method that can model early Drosophila embryogenesis on a personal computer. This quantitative calculation tool is simple enough to be useful for experimentalists in designing experiments yet detailed enough for theoreticians to derive new insights on the evolution of developmental genetic networks. By integrating the strengths of theoretical and experimental methods into a single engineering model that can compute the cascade of genetic networks in a real organism, I provide a new calculational tool that can apply current theory to current experimental data to study the evolution of developmental programs.     

Cellular pathways acting along the germband and in the amnioserosa may participate in germband retraction of the Drosophila melanogaster embryo

Germband retraction in Drosophila melanogaster, like most embryonic morphogenetic events in this organism and in higher eukaryotes, is not well understood. We have taken several approaches to study the relationships between previously identified mutations (u-shaped, serpent, hindsight and tailup) that selectively cause germband retraction defects in homozygous embryos, and a more pleiotropically acting locus, DER/faint little ball. Our observations from genetic, immunohistochemical, and embryo culture experiments suggest that the former four loci are elements of at least two parallel and partially redundant cellular pathways that affect germband retraction by acting in amnioserosal development or maintenance. An additional discrete and unique pathway, represented by DER/faint little ball, is likely to function in the germband itself. While the role of the amnioserosa during germband retraction appears to be permissive, the action of DER in the germband may be mediated by the cytoskeleton.     

Identification of trans-acting genes necessary for centromere function in Drosophila melanogaster using centromere-defective minichromosomes

Deletions in the Drosophila minichromosome Dp1187 were used to investigate the genetic interactions of trans-acting genes with the centromere. Mutations in several genes known to have a role in chromosome inheritance were shown to have dominant effects on the stability of minichromosomes with partially defective centromeres. Heterozygous mutations in the ncd and klp3A kinesin-like protein genes strongly reduced the transmission of minichromosomes missing portions of the genetically defined centromere but had little effect on the transmission of minichromosomes with intact centromeres. Using this approach, ncd and klp3A were shown to require only the centromeric region of the chromosome for their roles in chromosome segregation. Increased gene dosage also affected minichromosome transmission and was used to demonstrate that the nod kinesin-like protein gene interacts genetically with the centro mere, in addition to interacting with extracentromeric regions as demonstrated previously. The results presented in this study strongly suggest that dominant genetic interactions between mutations and centromere-defective minichromosomes could be used effectively to identify novel genes necessary for centromere function.     

Relative paucity of genes causing inviability in hybrids between Drosophila melanogaster and D. simulans

Using deficiencies from Drosophila melanogaster, we looked for genomic regions in the sister species D. simulans that could cause lethality when hemizygous on a hybrid genetic background. Such genotypes allow hemizygous genes from one species to interact with heterozygous genes from other species and may correspond to the kinds of genotypes causing Haldane's rule, the observation that if only one gender is sterile or inviable in species hybrids, it is nearly always the heterogametic sex. A survey of roughly 50% of the D. simulans genome (114 chromosome regions) revealed only four regions causing hybrid lethality and five causing severe reductions in hybrid viability. However, the viability of all of these genotypes was at least partially restored by rearing hybrids at lower temperature or using different genetic backgrounds from D. simulans. We therefore detected no D. simulans chromosome regions causing unconditional hybrid lethality, although several regions were shown to be deleterious under most tested temperatures and genetic backgrounds. The relative paucity of "inviability genes" supports the idea, suggested by work on other species, that hybrid inviability between closely related species might be caused by interactions among relatively few genes, while hybrid sterility may involve many more loci.     

New mutants of Drosophila melanogaster

Characteristics are given of 57 Drosophila melanogaster mutants catched in the South and Soeth-West Iran.     

Characterization of a Drosophila proximal-sequence-element-binding protein involved in transcription of small nuclear RNA genes

The semisynthesis of eel[L-alpha-aminosuberic acid]calcitonin (elcatonin) was accomplished by alpha-chymotrypsin-catalyzed coupling of two peptide segments in a single reaction without the protection of any functional group. The eel calcitonin-(10-32)-peptide was prepared by a gene manipulation. The esters of cyclic desamino nonapeptide (segment 1-9) were synthesized by the conventional solution method including a thermolysin-mediated resolution of DL-alpha-aminosuberic acid via one-step tripeptide synthesis leading to the 7-9 sequence. The main aim of this work was to determine the conditions for protease-catalyzed segment condensation while avoiding a concurrent cleavage of other proteolytically labile peptide bonds in the hormone. The alpha-chymotrypsin condensation strategy under usual conditions led to a complicated mixture of split products with an insignificant amount of the required peptide. When the coupling reaction was carried out at 0 degrees C, the reaction resulted in a satisfactory yield of elcatonin with the complete conversion of the acyl donor (1-9 segment) accompanied by negligible concurrent peptide bond digestion. The same strategy was employed for the preparation of analogous dicarba salmon calcitonin using a synthetic elcatonin-(10-32)-peptide. Both calcitonin analogs exhibited hypocalcemic activity corresponding to the international standard of elcatonin. We demonstrate in this work a peptide synthesis based on the combination of genetic engineering, chemical synthesis and proteinase-catalyzed segment condensation. This approach enables effective incorporation of an unnatural amino acid into calcitonins without the side-chain protection.     

黑腹果蝇热激蛋白基因家族的生物信息学分析

热激蛋白是细胞或生物体受到热激后新合成的一类遗传上高度保守的蛋白,在生物体中普遍存在,在细胞生长、发育、分化、基因转录等功能方面发挥重要的作用.本研究利用生物信息学方法首次对黑腹果蝇(Drosophila melanogaster)全部热激蛋白进行分析.结果表明,黑腹果蝇热激蛋白共有HSPC(HSP90)、HSPA(HSP70)、DNAJ(HSP40)、HSPB(小分子HSP)、HSPD(HSP60)、CCT(TRiC)等6个基因家族,不存在HSPE(HSP10)和HSPH(HSP110)家族,共有35个基因,新发现7个基因,命名为HSPBA5、HSPBB2、HSPBB3、DNAJA7、DNAJA8、HSPD5和HSPCB1.染色体定位表明,黑腹果蝇热激蛋白主要分布在2L、3L、2R、3R和X上.序列比对分析发现,黑腹果蝇热激蛋白家族序列高度保守.进化分析表明,他们有共同的祖先,可分为6个基因家族.     

virilizer regulates Sex-lethal in the germline of Drosophila melanogaster

BACKGROUND AND PURPOSE: Advancing age is associated with declines in motor function; understanding age-related changes in the basal ganglia, therefore, is imperative for comprehension of such functional changes. The purpose of this study was to examine the age, sex, and hemispheric differences in volume of the caudate nucleus, the putamen, and the globus pallidus. METHODS: In a sample of 148 healthy right-handed adults (18-77 years old) with no evidence of age-related motor disorders, we estimated the volume of the head of the caudate nucleus, the putamen, and the globus pallidus from MR images. RESULTS: The analyses revealed bilateral age-related shrinkage of the head of the caudate nucleus and the putamen in both sexes. In men, the age-related shrinkage of the caudate was stronger on the left, whereas, in women, the opposite trend was evident. In both sexes, age-related shrinkage of the right putamen was greater than of its left counterpart. The mild bilateral age-related shrinkage of the globus pallidus was observed only in men. In both sexes, we observed significant rightward asymmetry in the putamen, significant leftward asymmetry in the caudate, and no asymmetry in the globus pallidus. CONCLUSIONS: Bilateral age-related shrinkage of the neostriatum is found in healthy adults. The shrinkage of the globus pallidus is less pronounced and may be restricted to men only.     

A modifier screen in the eye reveals control genes for Krüppel activity in the Drosophila embryo

Irregular facets (If) is a dominant mutation of Drosophila that results in small eyes with fused ommatidia. Previous results showed that the gene Krüppel (Kr), which is best known for its early segmentation function, is expressed ectopically in If mutant eye discs. However, it was not known whether ectopic Kr activity is either the cause or the result of the If mutation. Here, we show that If is a gain-of-function allele of Kr. We then used the If mutation in a genetic screen to identify dominant enhancers and suppressors of Kr activity on the third chromosome. Of 30 identified Kr-interacting loci, two were cloned, and we examined whether they also represent components of a natural Kr-dependent developmental pathway of the embryo. We show that the two genes, eyelid (eld) and extramacrochaetae (emc), which encode a Bright family-type DNA binding protein and a helix-loop-helix factor, respectively, are necessary to achieve the singling-out of a unique Kr-expressing cell during the development of the Malpighian tubules, the excretory organs of the fly. The results indicate that the Kr gain-of-function mutation If provides a tool to identify genes that are active during eye development and that a number of them function also in the control of Kr-dependent developmental processes.