摘要:

AbstractInD. hydeitwo new mutants,In(1)f3andIN(5)Z, show obvious mosaic gene expression. Their phenotypic expression is susceptible to the breeding temperature and to the addition of a supernumerary Y chromosome to the chromosome set. In this respect the mutants resemble standard cases of position‐effect variegation based on the action of heterochromatin. However, since neither centromeric nor sex chromosomal heterochromatin apparently are involved, the mutations point to a new type of variegation provoked by euchromatic sections. The mosaic patterns of these mutants, in particular those ofIn(1)f3, will be describe

ISSN:0192-253X    

DOI:10.1002/dvg.1020090602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractWe have identified early embryo proteins related to the segmentation geneKrüppelby [35S]methionine pulse labelling and two‐dimensional gel electrophoresis. Protein synthesis differences shared by homozygous embryos of twoKrüppelalleles when compared to heterozygous and wild‐type embryos are reported. The study was extended to syncytial blastoderm stages by pulse labelling and gel analysis of single embryos, usingKrüppelspecific proteins from gastrula stages as molecular markers for identifying homozygousKrüppelembryos. Localized expression of interesting proteins was examined in embryo fragments. The earliest differences detected at nuclear migration stages showed unregulated synthesis in mutant embryos of two proteins that have stage specific synthesis in normal embryos. At the cellular blastoderm stage one protein was not synthesized and two proteins showed apparent shifts in isoelectric point in mutant embryos. Differences observed in older embryos included additional proteins with shifted isoelectric points and a number of qualitative and quantitative changes in protein synthesis. Five of the proteins with altered rates of synthesis in mutant embryos showed localized synthesis in normal embryos. The early effects observed are consistent with the hypothesis that theKrüppelproduct can be a negative or positive regulator of expression of other loci, while blastoderm and gastrula stage shifts in isoelectric point indicate that a secondary effect ofKrüppelfunction may involve post‐translational modification

ISSN:0192-253X    

DOI:10.1002/dvg.1020090603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractGenetic analysis has shown that the gap segmentation genehunchback (hb)is a member of the genetic hierarchy involved in pattern formation inDrosophila.To identify thehbgene, we have mapped the position ofhbmutant breakpoints within a chromosomal walk of the 85A region by genomic Southern blots and determined the transcription pattern of DNA from the walk. We detect a single gene within the domain defined by breakpoint mapping. We conclude that we have identified thehunchbackgene because three mutations that inactivatehbphysically interrupt or delete this gene. Northern analysis shows that thehbgene gives rise to at least five overlapping transcripts ranging in length from 2.6 to 3.5 kilobases. S1 nuclease and primer extension experiments demonstrate that the gene employs two promoters and three polyadenylation sites. The twohbpromoters have different temporal specificities. Transcripts arising from the upstream promoter are detected from 0–12 hours of embryogenesis as well as in adult female and male RNA preparations. Transcripts arising from the downstream promoter accumulate only from 0–6 hours of embryogenesis. During the syncytial blastoderm stage, transcripts from thehbgene accumulate over a broad anterior and a narrow posterior domain. This pattern sharpens during the late blastoderm/early gastrula stage to produce an embryo with two stripes of hybridization anterior and one stripe posterior. Later,hbtranscripts are detected within the ventral hypoderm in extended germ band stage embr

ISSN:0192-253X    

DOI:10.1002/dvg.1020090604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe mycelium of the fungusPhycomyces.essentially a giant multinucleate cell, produces two kinds of asexual reproductive structures, called macrophores and microphores, and a succession of structures for sexual reproduction. Following the treatment of spores with N‐methyl‐N′ ‐nitro‐N‐nitrosoguanidine, conditionalimbmutants have been isolated that form no macrophores at 26°C, but do at 14°C. At the restrictive temperature, fewimbmutants (2 of 13) develop microphores, and none is able to complete the sexual cycle. This suggests that genes responsible for macrophorogenesis are involved in microphorogenesis and in sexual development as well. Light reduces macrophorogenesis and totally abolishes microphorogenesis in the wild type under the conditions of our experiments. These photomorphogenetic effects require the normal function of genesmadAandmadB, which are responsible for phototropism. Light inhibits microphorogenesis in the twoimbmutants that form microphores at the restrictive temperature. Genetic alterations of carotenogenesis lead to an excess of microphores and a scarcity of macrophores in the dark, but they have little influence on vegetative reproduction

ISSN:0192-253X    

DOI:10.1002/dvg.1020090605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0192-253X    

DOI:10.1002/dvg.1020090606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0192-253X    

DOI:10.1002/dvg.1020090601

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY