Hsp60C is required in follicle as well as germline cells during oogenesis inDrosophila melanogaster (original) (raw)
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Genetic Analysis of Viable Hsp90 Alleles Reveals a Critical Role in Drosophila Spermatogenesis
Genetics, 1999
The Hsp90 chaperone protein maintains the activities of a remarkable variety of signal transducers, but its most critical functions in the context of the whole organism are unknown. Point mutations of Hsp83 (the Drosophila Hsp90 gene) obtained in two different screens are lethal as homozygotes. We report that eight transheterozygous mutant combinations produce viable adults. All exhibit the same developmental defects: sterile males and sterile or weakly fertile females. We also report that scratch, a previously identified male-sterile mutation, is an allele of Hsp82 with a P-element insertion in the intron that reduces expression. Thus, it is a simple reduction in Hsp90 function, rather than possible altered functions in the point mutants, that leads to male sterility. As shown by light and electron microscopy, all stages of spermatogenesis involving microtubule function are affected, from early mitotic divisions to later stages of sperm maturation, individualization, and motility. ...
FEBS Letters, 1999
The chaperonins are evolutionarily conserved essential cellular proteins that help folding newly synthesized or translocated proteins, spending ATP. We present here the molecular analysis of the hsp60 gene promoter region and of two Drosophila hsp60 ethyl methane sulfonate embryonic lethal alleles that have an identical phenotype. No heat shock element sequences were found in the 5P P region, supporting previous data (Kozlova, T. et al., 1997) which suggests that mitochondrial Drosophila melanogaster HSP60.1 is not heat inducible. By sequencing the lethal allele's entire open reading frame (ORF), we found a C-T transition in the hsp60 F409 allele that produces a serine to leucine change, apparently distorting the protein equatorial domain structure. No changes were found in the hsp60 G93 ORF. However, an analysis of the heterogeneous nuclear RNA levels showed a reduction of the hsp60 transcript in hsp60 G93 flies as compared to the wild-type. These data suggest that although the defects in the hsp60 gene produced by these alleles are at different levels, both behave as null mutations.
Developmental Biology, 1987
female sterile mutations that affect eggshell assembly in Drosophila have been mapped to the 7Cl-3 region of the X-chromosome. TEM of the mature eggshell of one of the alleles, fs(1)410, shows a lack of organization within the endochorion and an accumulation of electron dense material in the vitelline membrane of stage 14 eggchambers. SDS-PAGE of radiolabeled eggshell proteins shows that two proteins, ~67 and ~85, fail to accumulate in the fs(1)410 eggshell. In wild-type flies 985 is produced during stage 10 of oogenesis and then processed to ~6'7 in stages 13 and 14. Neither 985 nor an additional stage 10 specific follicle cell protein (~130) are detected in fs(1)410 or four of the mutant alleles. Short-term labeling studies, analyses of in vitro translation products, and the simultaneous occurrence of ~85 and ~130 as electrophoretic variants in geographic fly strains indicate ~85 is derived from ~130. Although major biochemical differences appear in stage 10, mutant and wild-type eggshells are morphologically indistinguishable until stages 13-14. These results suggest that follicle cell proteins synthesized during the time of vitelline membrane deposition (stage 10) are important for proper assembly of the chorion layers during stages 13 and 14,
Experientia, 1996
A homologue of the chaperonin protein of the HSP60 family has not been shown so far in Drosophila. Using an antibody specific to HSP60 family protein in Western blotting and immunocytochemistry, we showed that a 64-kDa polypeptide, homologous to the HSP60, is constitutively present in all tissues of Drosophila melanogaster throughout the life cycle from the freshly laid egg to all embryonic, larval and adult stages. A 64-kDa polypeptide reacting with the same antibody in Western blots is present in all species of Drosophila examined. Using Western blotting in conjunction with 35S-methionine labeling of newly synthesized proteins and immuno-precipitation of the labeled proteins with HSP60-specific antibody, it was shown that synthesis of the 64-kDa homologue of HSP60 is appreciably increased by heat shock only in the Malpighian tubules, which are already known to lack the common HSPs.
Expression and localization of Drosophila melanogaster hsp70 cognate proteins
Molecular and Cellular Biology, 1986
Monoclonal antibodies have been used to identify three proteins in Drosophila melanogaster that share antigenic determinants with the major heat shock proteins hsp70 and hsp68. While two of the proteins are major proteins at all developmental stages, one heat shock cognate protein, hsc70, is especially enriched in embryos. hsc70 is shown to be the product of a previously identified gene, Hsc4. We have examined the levels of hsp70-related proteins in adult flies and larvae during heat shock and recovery. At maximal induction in vivo, hsp70 and hsp68 never reach the basal levels of the major heat shock cognate proteins. Monoclonal antibodies to hsc70 have been used to localize it to a meshwork of cytoplasmic fibers that are heavily concentrated around the nucleus.
Experimental Cell Research, 2004
In this study, we present evidence that the asp function is required in oogenesis for germline cell divisions as well as for cyst polarity and oocyte differentiation. Consistent with previously described roles in spindle organization during Drosophila meiosis and mitosis, asp mutation leads to severe defects in spindle microtubule organization within the germarium. The mitotic spindles of the mutant cystocytes are composed by wavy microtubules and have abnormal poles that often lack g-tubulin. The fusome structure is also compromised. In the absence of asp function, the cystocyte divisions fail resulting in egg chamber with fewer than 16 germ cells. Moreover, the microtubule network within the developing germline cysts may assemble incorrectly in turn affecting the microtubule based transport of the specific determinants that is required during mid-oogenesis for the oocyte differentiation program.
Molecular genetics of oogenesis in Drosophila melanogaster
Invertebrate Survival Journal, 2004
Gonadal development requires complex differentiation programs leading to the production offunctional female and male gametes. Upon fertilization, while the male germ cell contributes to thenewly formed zygote only its genetic material, the female germ cell also supplies its cytoplasmiccomponents, including fundamental molecular cues on which early embryonic development will rely.Unravelling the mechanisms employed by animal species for building up their eggs is therefore achallenging task in developmental biology. As demonstrated by the impressive body of data producedin recent years, Drosophila melanogaster is a useful model system for attempting a step by stepdissection of the whole oogenesis process. Remarkable opportunities for comparative analyses are inturn expected to be provided by these studies, since it is becoming evident that conserved themesunderlie oogenesis in all animal species. In this review, we focus on few key differentiation eventsoccurring during egg chamber de...
Scientific Reports, 2018
Drosophila chorion represents a remarkable model system for the in vivo study of complex extracellular-matrix architectures. For its organization and structure, s38 protein is considered as a component of major importance, since it is synthesized and secreted during early choriogenesis. However, there is no evidence that proves its essential, or redundant, role in chorion biogenesis. Hence, we show that targeted downregulation of s38 protein, specifically in the ovarian follicle-cell compartment, via employment of an RNAi-mediated strategy, causes generation of diverse dysmorphic phenotypes, regarding eggshell’s regionally and radially specialized structures. Downregulation of s38 protein severely impairs fly’s fertility and is unable to be compensated by the s36 homologous family member, thus unveiling s38 protein’s essential contribution to chorion’s assembly and function. Altogether, s38 acts as a key skeletal protein being critically implicated in the patterning establishment of...