ISSN:0192-253X    

DOI:10.1002/dvg.1020140102

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

年代:1993

数据来源: WILEY

摘要:

AbstractIn the filamentous oomycete fungusAchlya, the differentiation of gamete bearing structures on vegetative hyphae of the male mating type, is induced by theAchlyasteroid hormone, antheridiol. Among the several metabolically labeled intracellular proteins whose synthesis or accumulation is altered by hormone treatment are steroid‐induced 85‐kDa and 68‐ to 78‐kDa proteins. The 85‐kDa protein was previously shown to be theAchlyaheat shock protein hsp85 [Bruntet al., 1990; Brunt and Silver, 1991], a component of the putativeAchlyasteroid hormone receptor. It was of interest to determine if the antheridiol‐induced “70‐kDa” proteins were hsp70‐family heat shock proteins and if hormone treatment‐induced changes in the level of hsp70 transcripts. Two differentAchlyahsp70 genomic sequences were cloned and used to investigate these questions. The two hsp70 sequences recognized two different mycelial transcript populations, one of which was regulated also by decreased glucose. Of note, both of the two hsp70 transcript populations were found to be regulated by antheridiol. The hormone‐induced chcnges in hsp70 transcript levels were temporally correlated with the onset of massive lateral hyphal branching and alterations in the pattern of secreted N‐linked glycoproteins which occur in hormone‐treated mycelia. To our kncwledge, this represents one of the first reports on changes in hsp70 proteins and transcripts during fungal differentiation. Our results may have implications for the role of heat shock proteins in hyphal branching and secretion in filamentous fungi and perhaps other cell types.

ISSN:0192-253X    

DOI:10.1002/dvg.1020140103

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe small (18‐kDa) heat shock proteins (hsps) of maize are encoded by a complex multigene family. In a previous report, we described the genetic information from cDNAs encoding two different members of the family. In this communication, we report the isolation and characterization of cDNA and genomic clones encoding information for a third member of this hsp family (c/gMHSP18–1). DNA fragments containing nucleotide sequences common to, or specific for, each of these characterized 18‐kDa genes were prepared and used as probes to assess the expression of these genes during microsporogenesis and development of the gametophyte in an inbred line of maize (Oh43). Our results demonstrate (1) that mRNA transcripts encoding the 18‐kDa hsps are expressed and/or accumulate during microsporogenesis, and (2) that genes encoding two of the characterized 18‐kDa hsps are expressed and/or accumulate independently, in a stage‐specific manner during microsporogenesis. These observations imply that the stage‐specific expression of particular 18‐kDa hsp genes results from gene‐specific regulation during microsporogenesis and gametophyte development rather than from an overall activation of the heat shock or stress response. © 1

ISSN:0192-253X    

DOI:10.1002/dvg.1020140104

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

年代:1993

数据来源: WILEY

摘要:

AbstractWe have isolated two genes fromZea maysencoding proteins of 82 and 81 kD that are highly homologous to theDrosophila83‐kD heat shock protein gene and have analyzed the structure and pattern of expression of these two genes during heat shock and development. Southern blot analysis and hybrid select translations indicate that the highly homologous hsp82 and hsp81 genes are members of a small multigene family composed of at least two and perhaps three or more gene family members. The deduced amino acid sequence of these proteins based on the nucleotide sequence of the coding regions shows 64‐88% amino acid homology to other hsp90 family genes from human, yeast,Drosophila, andArabidopsis.The promoter regions of both the hsp82 and hsp81 genes contain several heat shock elements (HSEs), which are putative binding sites for heat shock transcription factor (HSF) commonly found in the promoters of other heat shock genes. Gene‐specific oligonucleotide probes were synthesized and used to examine the mRNA expression patterns of the hsp81 and hsp82 genes during heat shock, embryogenesis, and pollen development. The hsp81 gene is only mildly heat inducible in leaf tissue, but is strongly expressed in the absence of heat shock during the premeiotic and meiotic prophase stages of pollen development and in embryos, as well as in heat‐shocked embryos and tassels. The hsp82 gene shows strong heat inducibility at heat‐shock temperatures (37–42°C) and in heat shocked embryos and tassels but is only weakly expressed in the absence of heat shock. Promoter‐GUS reporter gene fusions made and analyzed by transient expression assays in Black Mexican Sweet (BMS) Maize protoplasts also indicate that the hsp82 and hsp81 are regulated differentially. The hsp82 promoter confers strong heat‐inducible expression of the GUS reporter gene in heat‐treated cells (60‐ to 80‐fold over control levels), whereas the hsp81 promoter is only weakly heat inducible (5‐ to 10‐fold over control leve

ISSN:0192-253X    

DOI:10.1002/dvg.1020140105

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

年代:1993

数据来源: WILEY

摘要:

AbstractIn the present study, we have examined the regulation of expression of a newly isolated member of the hsp 30 gene family, hsp 30C. Using RT‐PCR, we found that this gene was first heat‐inducible at the tailbud stage of development. We also examined the expression of two microinjected modified hsp 30C gene constructs inXenopusembryos. One of the constructs had 404 bp of hsp 30C 5′‐flanking region, whereas the other had 3.6 kb. Both gene constructs had 1 kb of 3′‐flanking region. RT‐PCR assays were employed to detect the expression of these microinjected genes. The presence of extensive 5′‐ and 3′‐flanking regions of the hsp 30C gene did not confer proper developmental regulation, since heat‐inducible expression of both of the microinjected constructs was detectable at the midblastula stage. The premature expression of the microinjected hsp 30 gene was not a result of high plasmid copy number or the presence of plasmid DNA sequences. These results suggest that the microinjected genes contain all thecis‐acting DNA sequences required for correct heat‐inducible regulation but do not contain the elements required for the proper regulation of hsp 30 gene expression during development. It is possible that regulatory elements controlling the developmental expression of the hsp30 genes may reside upstream or downstream of the entire clu

ISSN:0192-253X    

DOI:10.1002/dvg.1020140106

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

年代:1993

数据来源: WILEY

摘要:

AbstractHeat‐shockedXenopusembryos have an unusually complex heat shock response. The dominant heat shock protein (Hsp) has a relative molecular mass (Mr) of 62,000 D (Hsp62). Affinity‐purified IgGs against the glycolytic enzyme pyruvate kinase (PK; EC 2.7.1.40) specifically immunoprecipitated Hsp62 from extracts of embryos that had been heat‐shocked at 37°C for 30 min. Thus, Hsp62 and pyruvate kinase are immunologically cross‐reacting. Electrophoretic separation of PK isoforms suggests that heat‐shockedXenopusembryos increase synthesis of an isoform of PK. Thermal denaturation studies suggest that this isoform has enhanced thermal stability. The identification of PK as an Hsp is discussed within the context of a physiological requirement for elevated levels of anaerobic glycolysis in heatstressed cells as a vital component of the acquisition of thermotolerance. © 1993Wile

ISSN:0192-253X    

DOI:10.1002/dvg.1020140107

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

年代:1993

数据来源: WILEY

摘要:

AbstractA 20‐kD protein identified as a subunit of the iron‐binding protein ferritin is present in S.purpuratusandL. pictussea urchin embryos. The synthesis of the protein is stimulated by an elevation in temperature or by an increase in iron supply. The developmental expression of this protein and its regulation during normal development and upon heat shock was investigated. InL. pictus, ferritin is present in the unfertilized egg and, as determined by Western blot analysis, its concentration remains approximately constant after fertilization up to the gastrulc‐pluteus stage; there is a small transient decrease in the level of the protein in the early blastula at a time coinciding with the first clear indication of its de novo synthesis. Northern blots reveal no cytoplasmic ferritin transcripts in the unfertilized egg, but there occurs a dramatic increase in the RNA level from the late morulaearly blastula stage (12–14 hr) to the mesenchyme blastula‐early gastrula (25–30 hr) stage. This developmentally regulated increase in the constitutive concentration of ferritin RNA is correlatable with the normal onset of synthesis of the protein. The overall degree and nature of induction of ferritin by heat is dependent on the developmental stage: at 10–16 hr postfertilization heat shock elicits an increase in both the concentration of RNA and the synthesis of the protein; in hatched blastula (18 hr) and in later embryos heat shock increases ferritin synthesis, without a corresponding increase in the mRNA level. It appears that different mechanisms operate in the developing sea urchin embryo to regulate the expression of ferritin during normal development and on exposure to heat stress, one dependent on the concentration of ferritin transcripts and another operating at the level of translational control. © 1993W

ISSN:0192-253X    

DOI:10.1002/dvg.1020140108

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

年代:1993

数据来源: WILEY

摘要:

AbstractTo determine differences in the patterns of expression ofDrosophilasmall heat shock proteins (shsp) during normal development in the absence of stress, proteins obtained from head, thorax and gonads of young (0–12 h, 3 days), middle‐aged (3–6 days) and 15‐ to 20‐day‐old adult flies were separated on SDS‐PAGE gels and blotted with monoclonal antibodies against hsp23 and hsp26. hsp23 was found in the heads and gonads of young males and females. In contrast, the maximum expression of hsp26 was seen in gonads of young flies, and it was only lightly detected in the brain. The expression of both proteins decreased as flies aged. This age‐related decrease was particularly striking for hsp23 in females. The immunoblot results obtained were complemented by immunostaining of thin parasagittal sections of whole fly bodies Hsp23 was found to be expressed in the brain, thoracic ganglion, fat body and gonads of young (0‐12 h) males and females. On the other hand, hsp26 was essentially detected in ovaries and testes of these young flies. The analysis of the tissue expression of both proteins demonstrate that each shsp has a distinct cellular localization. In the central nervous system, hsp23 and hsp26 were present in the neurocytes of the brain and the thoracic ganglion. In addition, hsp23 (but not hsp26) was also detected in the central neuropile of these two organs. In testis, hsp26 was localized in the cytoplasm of spermatocytes and, probably, in the spermatid bundles. In contrast, hsp23 was detected at the periphery of cells (membranes). In ovorioles of newborn females the expression of hsp26 was stronger, and the maximum expression of hsp23 was only reached in older (2 days and more) flies. These results demonstrate that each shsp possesses a specific spatial and temporal pattern of expression in adults ofDrosophila.The distinct tissue‐specific and age‐dependent expression of hsp23 and hsp26 suggests that these two proteins may have different functions in crucial organs ofDrosophila.

ISSN:0192-253X    

DOI:10.1002/dvg.1020140109

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

年代:1993

数据来源: WILEY

摘要:

AbstractWe examined the effect of aging on the expression of ubiquitin RNA and the binding of the ubiquitin polypeptide to proteins following heat shock inDrosophila melanogaster.Heat‐shocked adult flies transcribe two major RNA species‐one of 4.4 kb and one of about 6 kb that hybridize to the polyubiquitin‐encoding probe. Several less abundant RNAs were also observed but the 4.4‐kb band was present as the major RNA species in both stressed and nonstressed flies of both ages. The 6‐kb fragment was more abundant in heat shocked aged flies than in younger flies. The quantitative expression of the polyubiquitin gene increased in proportion to the duration of the heat stress. Moreover, the induction of the polyubiquitin RNA was markedly elevated during aging following heat shock. Hybridization of Northern blots with the monoubiquitin gene probe revealed a band of 0.9 kb that was not significantly affected by heat stress.We also investigated the relationship between the changes in polyubiquitin gene expression and the formation of ubiquitin‐protein complexes in aging heat‐shocked flies. Heat shock to old flies results in a significant increase in the level of proteins immunoprecipitated by anti‐ubiquitin antibodies. In the case of proteins synthesized 2 h before heat shock, most of the ubiquitinated proteins were of high molecular weight. For those proteins synthesized during a 30‐min heat shock and the 2 h following heat shock, two major immunoprecipitated bands were observed: an 80‐kD and a 70‐kD polypeptide. The ubiquitination of a 60 kD protein was also observed in nonstressed flies, but its for mation was drastically reduced following heat shock. For proteins synthesized during and after heat shock from both age groups, the major ubiquitinated polypeptide is 70 kD. In all age groups, more ubiquitin complexes were formed with proteins synthesized before heat shock, than with proteins synthesized either during or after heat shock. This suggests that cellular proteins synthesized at physiological temperatures are more sensitive to heat induced damage than those synthesized during stress. These data support the hypothesis that in aging flies, heat shock induces an unusually high concentration of abnormal proteins which are targeted for degradation by the ubiquitin‐dependent proteolytic system

ISSN:0192-253X    

DOI:10.1002/dvg.1020140110

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

年代:1993

数据来源: WILEY

ISSN:0192-253X    

DOI:10.1002/dvg.1020140101

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

年代:1993

数据来源: WILEY