ISSN:0192-253X    

DOI:10.1002/dvg.1020130402

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

年代:1992

数据来源: WILEY

摘要:

AbstractAntisense RNAs have been used for gene interference experiments in many cell types and organisms. However, relatively few experiments have been conducted with antisense genes integrated into the germ line. InDrosophilareduced ribosomal protein (r‐protein) gene function has been hypothesized to result in aMinutephenotype. In this report we examine the effects of antisense r‐protein 49 expression, a gene known to correspond to aMinutemutation An antisense rp49 gene driven by a strong and inducible promoter was transformed into theDrosophilagerm line. Induction of this gene led to the development of flies with weakMinutephenotypes and to the transient arrest of oogenesis. Parameters that may affect the success of antisense gene inactivation are discussed. © 1992 Wiley‐Lis

ISSN:0192-253X    

DOI:10.1002/dvg.1020130403

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

年代:1992

数据来源: WILEY

摘要:

AbstractEndosperm development in maize seed involves the multiplication, enlargement, and differentiation of cells with consequent accumulation of storage products. The storage protein genes, encoding zeins, and glutelins (multigene families) are expressed and developmentally regulated by different loci. Wild‐type lines and genotypes carrying mutations at loci affecting zein synthesis (o2, o7, fl2, andprol) were characterized at the molecular level and investigated by Northern analysis in order to define the expression of structural and regulatory genes. In situ hybridization in both wild‐type and mutant lines was performed to visualize the spatial distribution of transcripts representing each gene family, during endosperm development. The zein and glutelin mRNAs are expressed in all endosperm cells, except for the aleurone layer. However, each mRNA type accumulates at a different level in the various endosperm regions, thus allowing to recognize specific territories of expression for each storage protein mRNA within the tissue. The spatial expression patterns appear early for each gene type and are maintained during the course of endosperm development. Also, the quantitative distribution of the same transcripts in endosperm of mutant lines is specific for each mutant and different from that of the wild‐type. Furthermore, the amount of theO2transcript, present in the nucleus and cytoplasm of wild‐type cells, varies substantially in the differento2mutations considered, in one mutant almost exclusively confined within the nucleus. These data suggest a specific control of the spatial expression of storage protein genes and a heterogeneous molecular composition of protein bodies throughout the endosperm tissue. © 1992 Wiley

ISSN:0192-253X    

DOI:10.1002/dvg.1020130404

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

年代:1992

数据来源: WILEY

摘要:

AbstractTheBroad‐Complex(BR‐C) appears to encode factors that mediate ecdysone effects during the larva‐adult transition. The main goal of this study was to gain insight into what roles theBR‐Cmight play during oogenesis. The main findings are as follows. First, as determined by heteroallele studies and clonal analysis,de12is a somatic line mutation that appears to fall into thebroaddomain of theBR‐C.Second, thede12mutation is associated with the insertion of the gypsy transposon at position 169.5 (Chao and Guild, Embo J, 1986, 5:143–150) in theBR‐Cdomain. In its new context this gypsy element exhibits ovarianspecific activation. Both this gypsy activation and thede12phenotype are partially suppressible bysu(f)andsu(Hw).Third, we have identified a set of transcripts that cross‐hybridize withBR‐Csequence spanning the gypsy insertion site (166–179). There are significant differences in these cross‐hybridizing species, both in size and relative abundance, betweende12and its parent strain. Finally we have determined that inde12there is a premature arrest of chorion gene amplification in the late stages of oogenesis.

ISSN:0192-253X    

DOI:10.1002/dvg.1020130405

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

年代:1992

数据来源: WILEY

摘要:

AbstractDuring both spontaneous and thyroid hormone (TH)‐induced metamorphosis, theRana catesbeianatadpole undergoes postembryonic developmental changes in its liver which are necessary for its transition from an ammonotelic larva to a ureotelic adult. Although this transition ultimately results from marked increases in the activities and/or de novo synthesis of the urea cycle enzymes, the precise molecular means by which TH exerts this tissue‐specific response are presently unknown. Recent reports, using RNA from wholeXenopus laevistadpole homogenates and indirect means of measuring TH receptor (TR) mRNAs, suggest a correlation between the up‐regulation of TRβ‐mRNAs and the general morphological changes occurring during amphibian metamorphosis. To assess whether or not this same relationship exists in a TH‐responsive tissue, such as liver, we isolated and characterized a cDNA clone containing the complete nucleotide sequence for aR. catesbeianaurea cycle enzyme, ornithine transcarbamylase (OTC), as well as a genomic clone containing a portion of the hormone‐binding domain of aR. catesbeianaTRβ gene. Through use of these homologous sequences and a heterologous cDNA fragment encoding rat carbamyl phosphate synthetase (CPS), we directly determined the relative levels of the TRβ, OTC, and CPS mRNAs in liver from spontaneous and TH‐induced tadpoles. Our results establish that TH affects an up‐regulation of mRNAs for its own receptor prior to up‐regulating CPS and OTC mRNAs. Moreover, results with cultured tadpole liver demonstrate that TH, in the absence of any other hormonal influence, can affect an up‐regulation of both the TRβ and OTC mRNAs.

ISSN:0192-253X    

DOI:10.1002/dvg.1020130406

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

年代:1992

数据来源: WILEY

摘要:

AbstractArginine kinase displays a distinctive rise and fall in specific activity and specific protein levels during the prepupal stage ofDrosophiladevelopment with maximal activity occurring at morphological stage P3. This developmentally regulated peak is under the influence of ecdysone. Altered doses of the major ecdysone‐inducible “early” genes at cytological regions 75B and 2B5 alter this pattern of expression while altered doses of another major “early” gene at 74EF have no effect. We hypothesize that a product of the 2B5 locus and a product of the 75B locus interact to effect this developmental pattern of expression ofDrosophilaarginine kinase. © 1992 Wiley

ISSN:0192-253X    

DOI:10.1002/dvg.1020130407

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

年代:1992

数据来源: WILEY

摘要:

AbstractTheParamecium primaureliacell surface is covered with a high molecular weight protein called the surface antigen. Several genes encode alternative surface antigens, but only one is expressed at a time. In addition, each of these genes shows a high degree of allelic polymorphism.Paramecium primaureliastrains 156 and 168 have different alleles of the G antigen gene whose respective antigens can be distinguished in vivo using specific antibodies. An interallelic exclusion phenomenon has been previously described: 94% of the 156/168 heterozygotes express only the 156 allele of the G gene; 6% express both the 156 and the 168 alleles. The phenotype of the heterozygotes is determined at the time of macronuclear differentiation. We have investigated the molecular basis for the different heterozygous phenotypes. Both mRNAs are always produced, and the 156 mRNA is always more abundant than the 168 mRNA. The relative amounts of these messages, however, vary greatly between different heterozygotes and parallel their phenotype. Pushing the analysis further, we show that the copy number of each allele in the macronucleus correlates with the relative amounts of the mRNAs. However, allelic dosage alone is not sufficient to explain the variations of the mRNA ratio. The G antigen gene is located near a telomere in the macronucleus. We show that the distance between the 156G gene and the telomere is different in homozygotes and heterozygotes. It also varies among heterozygotes and is correlated with the mRNA ratio. Thus, we have identified two different parameters, both linked to the genome rearrangements occurring during macronuclear differentiation, that correlate with the relative expression of the two alleles. Two hypotheses concerning the influence of the telomere position on the expression of the gene are discussed. © 1992 Wiley‐Liss, I

ISSN:0192-253X    

DOI:10.1002/dvg.1020130408

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

年代:1992

数据来源: WILEY

ISSN:0192-253X    

DOI:10.1002/dvg.1020130401

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

年代:1992

数据来源: WILEY