New sex-linked mutation of wings fragility with age-depended expression (<Emphasis Type="Italic">fw</Emphasis>) in <Emphasis Type="Italic">Musca domestica</Emphasis> L.

A mutation of wing fragility that was not yet been revealed in adult housefly is described. Criss-cross inheritance of the character of fragility of the wing blade, which indicates localization of gene (fw) for this character in the X chromosome. Phenotypic expression of the mutant allele depends on sex. In male flies, the mutant allele in hemizygous state is expressed at the age of 2–3 weeks and older with penetrance close to 100%. In females, the mutant allele in homozygous state is lethal and in heterozygous state, totally recessive.     

Transvection in the Drosophila Ultrabithorax Gene: A Cbx(1) Mutant Allele Induces Ectopic Expression of a Normal Allele in Trans

In wild-type Drosophila melanogaster larvae, the Ultrabithorax (Ubx) gene is expressed in the haltere imaginal discs but not in the majority of cells of the wing imaginal discs. Ectopic expression of the Ubx gene in wing discs can be elicited by the presence of Contrabithorax (Cbx) gain-of-function alleles of the Ubx gene or by loss-of-function mutations in Polycomb (Pc) or in other trans-regulatory genes which behave as repressors of Ubx gene activity. Several Ubx loss-of-function alleles cause the absence of detectable Ubx proteins (UBX) or the presence of truncated UBX lacking the homeodomain. We have compared adult wing phenotypes with larval wing disc UBX patterns in genotypes involving double mutant chromosomes carrying in cis one of those Ubx mutations and the Cbx1 mutation. We show that such double mutant genes are (1) active in the same cells in which the single mutant Cbx1 is expressed, although they are unable to yield functional proteins, and (2) able to induce ectopic expression of a normal homologous Ubx allele in a part of the cells in which the single mutant Cbx1 is active. That induction is conditional upon pairing of the homologous chromosomes (the phenomenon known as transvection), and it is not mediated by UBX. Depletion of Pc gene products by Pc3 mutation strongly enhances the induction phenomenon, as shown by (1) the increase of the number of wing disc cells in which induction of the homologous allele is detectable, and (2) the induction of not only a paired normal allele but also an unpaired one.     

Rediscovery and further characterization of the aeroplane (ae) wing posture mutation in Drosophila melanogaster.

In 1931, Theodore Quelprud characterized a novel spontaneous mutation in Drosophila melanogaster, which was named aeroplane (ae) based on its abnormal wing posture. Although the characterization of the original ae locus was minimal, it is very likely that another allele of this extinct mutation has now been identified. aeroplane-like (ae-l) was isolated as a by-product of a transformation experiment. The apparent wing paralysis is not caused by any obvious abnormalities in the thorax, wing, indirect flight muscles or direct flight muscles. Classical genetic complementation analyses of ae-l with other genes in the region suggest that it represents an allele of a novel locus. Unexpectedly, a molecular examination revealed that the physical lesion identified in the ae-l mutant is exceptionally close to the homeotic gene teashirt (tsh) and, indeed, may represent an unusual allele of teashirt.     

Isolation and Characterization of a Phosphatidylethanolamine-Deficient Mutant of Bacillus subtilis

A mutant of Bacillus subtilis ATCC 6051 deficient in phosphatidylethanolamine, an important membrane lipid, was isolated by a combination of nitrosoguanidine mutagenesis and penicillin concentration of auxotrophs employing phosphatidylethanolamine as a supplement. The mutant was compared to the parent strain with regard to lipid composition, growth, osmotic fragility, and staining character and differed substantially in each category. In addition to scant amounts of phosphatidylethanolamine, the mutant contained phosphatidylglycerol, cardiolipin, lysyl phosphatidylglycerol, and diglucosyldiglyceride, though in amounts differing from those found in the parent strain. The mutant was unable to grow appreciably on synthetic media, had enhanced osmotic fragility of protoplasts, and resisted decolorization in staining.     

The defective dorsal discs gene of Drosophila is required for the growth of specific imaginal discs

The wild-type allele of the gene defective dorsal discs (ddd) is required for the normal development of the dorsal thoracic discs in Drosophila melanogaster. In ddd mutant larvae the dorsal discs (wing, haltere, and humeral) are greatly reduced in size or absent while the ventral discs (leg) are unaffected. We have examined the function of the ddd+ gene in wing development. The ddd+ product is not involved in the initial determination of wing cells but rather is required for their subsequent proliferation during the larval period. Analysis of chimaeras shows that there is a requirement for ddd+ gene expression in wing discs, but it is sufficient for normal development that only some cells in a disc express the gene. We propose that the ddd+ product is involved in the synthesis of a factor which is required for the normal growth of wing discs and which can be transferred between wing disc cells.     

The drosophila aeroplane mutant is caused by an I-element insertion into a tissue-specific teashirt enhancer motif.

In Drosophila melanogaster, aeroplane (ae) is a regulatory allele of teashirt (tsh), and the mutant wing posture phenotype of homozygous ae flies is caused by a defect in the hinge region of the wing, whereby the base of the wing at the proximal ventral radius is fused to the thorax in the region of the pleural wing process. The apparent paralysis of the wings and the drooping halteres are caused by an I-element insertion into a 3' noncoding sequence of tsh. The cis-acting regulatory element interrupted by the I element is required, to drive tsh expression in the regions of the developing adult that give rise to proximal wing and haltere tissues. Loss of this expression results in the fusion of the proximal structures of the wing and halteres to the thoracic cuticle. Further characterization of this tsh regulatory motif has now identified an additional enhancer activity directing tsh expression in tissues forming portions of the midgut. Subdivision of this midgut enhancer activity has identified putative negatively acting motifs.     

OsCesA4的等位基因Bc7(t)的精细定位和分离

水稻中已经发现并确认了许多脆秆突变体,本研究利用60Co-γ射线诱变粳稻品种中花11得到一脆秆突变体,命名为bc7(t)。与野生型相比,该突变体除了整个植株变脆、纤维素含量降低约10%外,表型与野生型品种相似。遗传分析表明该突变性状受控于单隐性基因,并将该基因精细定位在第1染色体长臂上8.4kb的区段内,基因注释信息表明该区域仅有一个编码纤维素合酶催化亚基(CesA)的基因,与OsCesA4基因等位。进一步的测序分析发现,在突变体中该基因的第10个外显子和第10个内含子的连接处缺失了7个碱基,导致阅读框改变而不能编码功能正常的蛋白。此外,RNA干涉试验表明,将Bc7(t)基因敲除,得到的所有转基因植株表现出类似突变体的脆性。OsCesA4新等位基因的发掘有助于阐明水稻细胞壁的生物合成机理,本文同时也讨论了该突变体用作动物饲料的潜在利用价值。     

Clinical and molecular findings in osteoporosis-pseudoglioma syndrome

Mutations in the low-density lipoprotein receptor-related protein 5 gene (LRP5) cause autosomal recessive osteoporosis-pseudoglioma syndrome (OPPG). We sequenced the coding exons of LRP5 in 37 probands suspected of having OPPG on the basis of the co-occurrence of severe congenital or childhood-onset visual impairment with bone fragility or osteoporosis recognized by young adulthood. We found two putative mutant alleles in 26 probands, only one mutant allele in 4 probands, and no mutant alleles in 7 probands. Looking for digenic inheritance, we sequenced the genes encoding the functionally related receptor LRP6, an LRP5 coreceptor FZD4, and an LRP5 ligand, NDP, in the four probands with one mutant allele, and, looking for locus heterogeneity, we sequenced FZD4 and NDP in the seven probands with no mutations, but we found no additional mutations. When we compared clinical features between probands with and without LRP5 mutations, we found no difference in the severity of skeletal disease, prevalence of cognitive impairment, or family history of consanguinity. However, four of the seven probands without detectable mutations had eye pathology that differed from pathology previously described for OPPG. Since many LRP5 mutations are missense changes, to differentiate between a disease-causing mutation and a benign variant, we measured the ability of wild-type and mutant LRP5 to transduce Wnt and Norrin signal ex vivo. Each of the seven OPPG mutations tested, had reduced signal transduction compared with wild-type mutations. These results indicate that early bilateral vitreoretinal eye pathology coupled with skeletal fragility is a strong predictor of LRP5 mutation and that mutations in LRP5 cause OPPG by impairing Wnt and Norrin signal transduction.     

The function of PS integrins in Drosophila wing morphogenesis.

Integrins are found on many cell types during the development of most organisms. In Drosophila their functions can be analysed genetically. An analysis of lethal mutations in a PS integrin gene showed that the integrins were required for muscle attachment and for certain cell sheet migrations during embryogenesis. In this paper we use viable mutations in integrin component genes to look at integrin function in the later stages of development of one adult structure, the wing. We show that two known viable mutations, one which has its primary effect on the fly's escape response, the other on wing morphogenesis, are mutations in the beta and PS2alpha subunits, respectively, of the PS integrins. The mutation non-jumper (mys(mj42)) in the beta subunit leads to wasting of the thoracic jump muscles. Flies in which the dosage of this allele is reduced (and no wildtype copy is present) show defects also in wing morphogenesis. The two surfaces of the wing fail to connect properly, resulting in 'blistering' of the wing and the formation of extra crossveins. The mutation in the gene for the PS2alpha integrin subunit, inflated, also leads to a failure in wing surface apposition and consequent wing blistering. When the two mutations are combined, the mutant phenotype is greatly enhanced. Thus, one of the roles of the PS integrins in late Drosophila development is to ensure the correct apposition and patterning of the wing epithelia.     

Roles for scalloped and vestigial in regulating cell affinity and interactions between the wing blade and the wing hinge

The scalloped and vestigial genes are both required for the formation of the Drosophila wing, and recent studies have indicated that they can function as a heterodimeric complex to regulate the expression of downstream target genes. We have analyzed the consequences of complete loss of scalloped function, ectopic expression of scalloped, and ectopic expression of vestigial on the development of the Drosophila wing imaginal disc. Clones of cells mutant for a strong allele of scalloped fail to proliferate within the wing pouch, but grow normally in the wing hinge and notum. Cells overexpressing scalloped fail to proliferate in both notal and wing-blade regions of the disc, and this overexpression induces apoptotic cell death. Clones of cells overexpressing vestigial grow smaller or larger than control clones, depending upon their distance from the dorsal-ventral compartment boundary. These studies highlight the importance of correct scalloped and vestigial expression levels to normal wing development. Our studies of vestigial-overexpressing clones also reveal two further aspects of wing development. First, in the hinge region vestigial exerts both a local inhibition and a long-range induction of wingless expression. These and other observations imply that vestigial-expressing cells in the wing blade organize the development of surrounding wing-hinge cells. Second, clones of cells overexpressing vestigial exhibit altered cell affinities. Our analysis of these clones, together with studies of scalloped mutant clones, implies that scalloped- and vestigial-dependent cell adhesion contributes to separation of the wing blade from the wing hinge and to a gradient of cell affinities along the dorsal-ventral axis of the wing.     

A genetic sexing system to improve the sterile insect technique against the Mediterranean fruit fly

The autosomal recessive allele v wing (v) in the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), produces flies that when reared at 30 degrees C have stubby wings. The mutant was used to construct a translocation-based genetic sexing system in an attempt to improve the efficiency and effectiveness of the sterile insect release method for field control.     

应用果蝇yellow基因的分子模式分析基因转应作用(英文)

基因转应作用（ｔｒａｎｓｖｅｃｔｉｏｎ）是基因表达的一种方式,这种方式是由等位基因配对及其相互作用所介导的。基因转应作用的现象已在果蝇的多种基因中发现。这种作用可产生正负两种效应。而且,在其它物种中,也逐渐发现了类似的现象。例如,在植物中的基因沉默现象（ｇｅｎｅｓｉｌｅｎｃｉｎｇ）以及在小鼠中的基因转激活作用（ｔｒａｎｓａｃｔｉｖａｔｉｏｎ）等。因此,阐明基因转应作用的机理,将有助于了解基因表达调节及增强子调控活动的分子基础。本文应用果蝇ｙｅｌｏｗ基因为模式来探讨基因转应作用的分子机制。前期研究表明,ｙｅｌｏｗ基因转应作用发生于ｇｙｐｓｙ诱导的ｙ２突变种和ｙｅｌｏｗ亚等位基因（ｙｈ）之间。为了证实是否ｇｙｐｓｙ是基因转应作用所必需的ＤＮＡ元件,我们鉴定了一种新的ｙｅｌｏｗ突变种,称为ｙ２３７４。ｙ２３７４突变是一种基因表达的组织特异性改变,这一改变使ｙ２３７４果蝇在翅和身体部位表皮着色呈突变型。通过遗传分析表明,ｙ２３７４也可与ｙｈ（如ｙ１＃８）产生基因转应作用。ｙ１＃８是一种无效的ｙｅｌｏｗ等位基因,它包含一个启动子和部分编码区序列的缺失。然而,当ｙ２３７４与ｙ１＃８杂交后,其杂交后代的表现型可由ｙ２３７     

Wingless mutation inDrosophila melanogaster

A temperature sensitive lethal allele of thewingless locus ofDrosophila melanogaster together with previously studied lethal and viable alleles in this locus, has been used to study some properties of this locus. These studies show the existence of two lethal phases for thewingless lesion; one during embryogenesis and another during pupation. By growing embryos with temperature sensitivewingless lesion at the permissive temperature and letting the larvae develop at non-permissive temperature, a large-scale cell death and subsequent regeneration were seen to occur in the mutant wing discs. This cell death followed by regeneration alters the normal developmental potential of the wing disc. Disc transplantation experiments show that these discs are incapable of differentiating into wing blade structures.     

Embryonic Head Involution and Rotation of Male Terminalia Require the Drosophila Locus Head Involution Defective

We have characterized the head involution defective (hid) locus which is located within the chromosomal region 75B8-C1,2. During the morphogenetic reorganization of the embryonic head region, hid+ function is necessary for the movement of the dorsal fold across the procephalon and clypeolabrum, a process that forms the frontal sac. The absence of the frontal sac in the hid mutant embryos affects the formation of the dorsal bridge and disrupts the development of the larval cephalopharyngeal skeleton. In addition to its embryonic role, this same hid function is also required during pupal development for the 360 degrees rotation of the male terminalia about the anterior-posterior body axis, and for a late step of wing blade morphogenesis. Although the abnormal wing phenotype caused by the Wrinkled (W) mutation is quite different from the one resulting from the loss-of-function hid mutations, the characterization of EMS-induced W revertants reveals that W is actually an antimorphic allele of hid.