The Xenopus Oocyte as an in Vitro Translation and Expression System for Chemosensory — Specific Gene Products

1990 ◽  
pp. 87-95
Author(s):  
Thomas V. Getchell ◽  
Frank L. Margolis
Keyword(s):  
Xenopus Oocyte ◽  
Expression System ◽  
In Vitro Translation ◽  
Specific Gene ◽  
Gene Products

scholarly journals Transcription of Candidate Virulence Genes ofHaemophilus ducreyi during Infection of Human Volunteers

2001 ◽  
Vol 69 (3) ◽  
pp. 1483-1487 ◽  
Author(s):  
Robert E. Throm ◽  
Stanley M. Spinola
Keyword(s):  
Experimental Infection ◽  
Virulence Genes ◽  
Human Model ◽  
Specific Gene ◽  
Gene Products ◽  
Virulence Determinants ◽  
Reverse Transcription Pcr ◽  
Human Volunteers

ABSTRACT Haemophilus ducreyi expresses several putative virulence factors in vitro. Isogenic mutant-to-parent comparisons have been performed in a human model of experimental infection to examine whether specific gene products are involved in pathogenesis. Several mutants (momp, ftpA, losB, lst, cdtC, and hhdB) were as virulent as the parent in the human model, suggesting that their gene products did not play a major role in pustule formation. However, we could not exclude the possibility that the gene of interest was not expressed during the initial stages of infection. Biopsies of pustules obtained from volunteers infected with H. ducreyiwere subjected to reverse transcription-PCR. Transcripts corresponding to momp, ftpA, losB, lst, cdtB, and hhdA were expressed in vivo. In addition, transcripts for other putative virulence determinants such as ompA2, tdhA, lspA1, andlspA2 were detected in the biopsies. These results indicate that although several candidate virulence determinants are expressed during experimental infection, they do not have a major role in the initial stages of pathogenesis.

Effect of diabetes and insulin treatment of diabetic rats on total RNA, poly(A)+ RNA, and mRNA in skeletal muscle

1991 ◽  
Vol 260 (3) ◽  
pp. C409-C416 ◽  
Author(s):  
J. D. Kent ◽  
S. R. Kimball ◽  
L. S. Jefferson
Keyword(s):  
Skeletal Muscle ◽  
Ribosomal Rna ◽  
Time Course ◽  
Diabetic Rats ◽  
In Vitro Translation ◽  
Specific Gene ◽  
Insulin Administration ◽  
Tissue Mass ◽  
Total Rna

We have assessed the time course of alterations in several biochemical parameters and expression of specific mRNAs in gastrocnemius muscle following both the induction of diabetes and the administration of insulin to diabetic rats. Muscle mass, total RNA, and total protein were reduced, whereas poly(A)+ RNA relative to total RNA was increased following the induction of diabetes. All the above parameters, with the exception of poly(A)+ RNA, were reciprocally and rapidly altered following administration of insulin to 3-day diabetic animals. These changes suggest that during the induction of diabetes 1) total cellular protein is reduced at a rate that is less than the reduction in gastrocnemius mass, whereas RNA is reduced at a rate 1.5 times the reduction in tissue mass, and 2) poly(A)+ RNA is elevated relative to total RNA. After insulin administration, there appears to be coordinate synthesis of both poly(A)+ RNA and ribosomal RNA, assuming 85% of total RNA is ribosomal. Therefore, we conclude that poly(A)+ RNA is more stable than ribosomal RNA during diabetes, whereas the amounts of poly(A)+ RNA and ribosomal RNA are increased at the same rates following insulin administration to diabetic animals. Analysis of expression of specific gene products over the same time course, as assessed by in vitro translation of total RNA followed by two-dimensional gel analysis, suggests that there are a few mRNAs that are very rapidly altered in response to insulin administration. The mRNAs that are altered demonstrate variable temporal patterns of either repression or full or transient expression. These rapid, but limited, alterations in gene expression may prove important in the development of the defects that occur in skeletal muscle in response to diabetes.

scholarly journals The SPS4 gene of Saccharomyces cerevisiae encodes a major sporulation-specific mRNA.

1986 ◽  
Vol 6 (12) ◽  
pp. 4478-4485 ◽  
Author(s):  
A T Garber ◽  
J Segall
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Polyacrylamide Gel Electrophoresis ◽  
Specific Protein ◽  
Polyacrylamide Gel ◽  
In Vitro Translation ◽  
Specific Gene ◽  
Alpha Cells ◽  
Two Dimensional ◽  
Isoelectric Ph

The SPS4 gene of Saccharomyces cerevisiae, a sporulation-specific gene identified previously in a differential hybridization screen of a genomic yeast DNA library, has been characterized further. The protein encoded by this gene was inferred from its nucleotide sequence to be 38,600 daltons with an isoelectric pH of 8.2. Consistent with this, two-dimensional polyacrylamide gel electrophoresis of the in vitro translation products of RNA purified by hybridization with the cloned SPS4 DNA indicated that the SPS4 gene product is a 39-kilodalton, basic protein. This protein was found to be identical in size and charge to a major, sporulation-specific protein identified in a two-dimensional polyacrylamide gel electrophoretic comparison of the in vitro translation products of total RNA from sporulating MATa/MAT alpha cells and asporogenous MAT alpha/MAT alpha cells. A MATa/MAT alpha strain homozygous for a partial deletion of the SPS4 gene appeared, however, to be unaffected in its ability to form viable ascospores.

scholarly journals Inefficient homooligomerization contributes to the dependence of myogenin on E2A products for efficient DNA binding.

1991 ◽  
Vol 11 (7) ◽  
pp. 3633-3641 ◽  
Author(s):  
T Chakraborty ◽  
T J Brennan ◽  
L Li ◽  
D Edmondson ◽  
E N Olson
Keyword(s):  
Dna Binding ◽  
Gene Activation ◽  
Binding Activity ◽  
Specific Gene ◽  
Gene Products ◽  
Basic Domain ◽  
High Affinity ◽  
Dna Binding Activity

Myogenin is a muscle-specific transcription factor that can activate myogenesis; it belongs to a family of transcription factors that share homology within a basic region and an adjacent helix-loop-helix (HLH) motif. Although myogenin alone binds DNA inefficiently, in the presence of the widely expressed HLH proteins E12 and E47 (encoded by the E2A gene), it forms heterooligomers that bind with high affinity to a DNA sequence known as a kappa E-2 site. In contrast, E47 and to a lesser extent E12 are both able to bind the kappa E-2 site relatively efficiently as homooligomers. To define the relative contributions of the basic regions of myogenin and E12 to DNA binding and muscle-specific gene activation, we created chimeras of the two proteins by swapping their basic regions. We showed that myogenin's weak affinity for the kappa E-2 site is attributable to inefficient homooligomerization and that the myogenin basic domain alone can mediate high-affinity DNA binding when placed in E12. Within a heterooligomeric complex, two basic regions were required to form a high-affinity DNA-binding domain. Basic-domain mutants of myogenin or E2A gene products that cannot bind DNA retained the ability to oligomerize and could abolish DNA binding of the wild-type proteins in vitro. These myogenin and E2A mutants also acted as trans-dominant inhibitors of muscle-specific gene activation in vivo. These findings support the notion that muscle-specific gene activation requires oligomerization between myogenin and E2A gene products and that E2A gene products play an important role in myogenesis by enhancing the DNA-binding activity of myogenin, as well as other myogenic HLH proteins.

Rapid changes in gene expression in response to microbial elicitation

1986 ◽  
Vol 314 (1166) ◽  
pp. 411-426 ◽  
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Chalcone Synthase ◽  
Blot Hybridization ◽  
Enzyme Synthesis ◽  
Chalcone Isomerase ◽  
Colletotrichum Lindemuthianum ◽  
Specific Gene ◽  
Gene Products

Treatment of cell suspension cultures of French bean ( Phaseolus vulgaris ) with polysaccharide elicitor molecules from cell walls of the anthracnose fungus, Colletotrichum lindemuthianum , results in the rapid accumulation of isoflavonoid phytoalexins, deposition of wall-bound phenolic compounds and synthesis of hydroxyproline-rich glycoproteins. These changes are dependent upon a highly selective induction of gene products, including the enzymes L-phenylalanine ammonia-lyase, cytochrome P450-dependent cinnamic acid 4-hydroxylase, chalcone synthase, chalcone isomerase, prolyl hydroxylase and protein: arabinosyl transferase. Use of in vivo labelling, in vitro translation and RNA blot hybridization techniques has shown that these elicitormediated changes arise from rapid but transient induction of enzyme synthesis, resulting from the accumulation of specific mRNAs. Similar phenomena are observed in bean hypocotyls at the onset of phytoalexin synthesis in response to infection by incompatible and compatible races of C. lindemuthianum . In bean, both L-phenylalanine ammonia-lyase and chalcone synthase are encoded by multigene families and, at the protein level, both exhibit subunit and intact enzyme polymorphism. A number of less than full-length phenylalanine ammonialyase copy DNAs containing identical open reading frames have been produced from mRNA from elicitor-induced bean cells. Analysis of phenylalanine ammonia-lyase genomic clones predicts the presence of enzyme forms of differing amino acid sequence. In cultured bean cells, elicitor differentially induces the two apparent phenylalanine ammonia-lyase iso-forms with the lowest K m values. In addition to transcriptional control of the appearance of specific gene products, post-translational processes may result in increased subunit polymorphism for phenylalanine ammonia-lyase, and in the activation of chalcone isomerase. Changes in endogenous phenylpropanoid intermediate pools may signal the rapid removal of phenylalanine ammonia-lyase activity, in addition to exerting less specific inhibitory effects on the formation and/or activity of the mRNAs encoding phenylalanine ammonia-lyase and other phytoalexin biosynthetic enzymes.

scholarly journals Repression of the albumin gene in Novikoff hepatoma cells.

1982 ◽  
Vol 2 (3) ◽  
pp. 258-266 ◽  
Author(s):  
Y G Capetanaki ◽  
C N Flytzanis ◽  
A Alonso
Keyword(s):  
Rat Liver ◽  
Cdna Probe ◽  
Hepatoma Cells ◽  
In Vitro Translation ◽  
Specific Gene ◽  
Transcriptional Level ◽  
Novikoff Hepatoma ◽  
Albumin Gene ◽  
Albumin Mrna

Novikoff hepatoma cells have lost their capacity to synthesize albumin. As a first approach to study the mechanisms underlying this event, in vitro translation in a reticulocyte system was performed using total polyadenylated mRNA from rat liver and Novikoff hepatoma cells. Immunoprecipitation of the in vitro translation products with albumin-specific antibody revealed a total lack of albumin synthesis in Novikoff hepatoma, suggesting the absence of functional albumin mRNA in these cells. Titration experiments using as probe albumin cDNA cloned in pBR322 plasmid demonstrated the absence of albumin-specific sequences in both polysomal and nuclear polyadenylated and total RNA from Novikoff cells. This albumin recombinant plasmid was obtained by screening a rat liver cDNA library with albumin [32P]cDNA reverse transcribed from immuno-precipitated mRNA. The presence of an albumin-specific gene insert was documented with translation assays as well as by restriction mapping. Repression of the albumin gene at the transcriptional level was further demonstrated by RNA blotting experiments using the cloned albumin cDNA probe. Genomic DNA blots using the cloned albumin cDNA as probe did not reveal any large-scale deletions, insertions, or rearrangements in the albumin gene, suggesting that the processes involved in the suppression of albumin mRNA synthesis do not involve extensive genomic rearrangements.

Functional expression and RNA binding analysis of the interferon-induced, double-stranded RNA-activated, 68,000-Mr protein kinase in a cell-free system

1991 ◽  
Vol 11 (11) ◽  
pp. 5497-5505
Author(s):  
M G Katze ◽  
M Wambach ◽  
M L Wong ◽  
M Garfinkel ◽  
E Meurs ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Expression System ◽  
In Vitro Translation ◽  
Initiation Factor ◽  
Alpha Subunit ◽  
Single Amino Acid ◽  
Free System

Eukaryotic viruses have devised numerous strategies to downregulate activity of the interferon-induced, double-stranded (dsRNA)-activated protein kinase (referred to as p68 on the basis of its Mr of 68,000 in human cells). Viruses must exert this control to avoid extensive phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF-2) by p68 and the resultant negative effects on protein synthesis initiation. To begin to define the molecular mechanisms underlying this regulation, we optimized expression of p68 in an in vitro transcription-translation system utilizing the full-length cDNA clone. The in vitro-expressed kinase was autophosphorylated in response to dsRNAs and heparin in a manner similar to that for the native p68 provided that the kinase inhibitor, 2-aminopurine, was present during the in vitro translation reaction. Further, the activated kinase efficiently phosphorylated its natural substrate, the alpha subunit of eIF-2. Binding experiments revealed that the expressed kinase complexed with the dsRNA activator, reovirus dsRNA, as well as the adenovirus-encoded inhibitor, VAI RNA. Interestingly, both the reovirus RNAs and VAI RNA also complexed with protein kinase molecules that lacked the carboxyl terminus and all catalytic domains. Deletion analysis confirmed that the p68 amino terminus contained critical determinants for reovirus dsRNA and VAI RNA binding. Further, reovirus dsRNA efficiently bound to, but failed to activate, p68 kinase molecules containing a single amino acid substitution in the invariant lysine 295 present in catalytic domain II. Taken together, these data demonstrate that this expression system permits a detailed mutagenic analysis of the regions of p68 required for interaction with virus-encoded activators and repressors.

The SPS4 gene of Saccharomyces cerevisiae encodes a major sporulation-specific mRNA

1986 ◽  
Vol 6 (12) ◽  
pp. 4478-4485
Author(s):  
A T Garber ◽  
J Segall
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Polyacrylamide Gel Electrophoresis ◽  
Specific Protein ◽  
Polyacrylamide Gel ◽  
In Vitro Translation ◽  
Specific Gene ◽  
Alpha Cells ◽  
Two Dimensional ◽  
Isoelectric Ph

The SPS4 gene of Saccharomyces cerevisiae, a sporulation-specific gene identified previously in a differential hybridization screen of a genomic yeast DNA library, has been characterized further. The protein encoded by this gene was inferred from its nucleotide sequence to be 38,600 daltons with an isoelectric pH of 8.2. Consistent with this, two-dimensional polyacrylamide gel electrophoresis of the in vitro translation products of RNA purified by hybridization with the cloned SPS4 DNA indicated that the SPS4 gene product is a 39-kilodalton, basic protein. This protein was found to be identical in size and charge to a major, sporulation-specific protein identified in a two-dimensional polyacrylamide gel electrophoretic comparison of the in vitro translation products of total RNA from sporulating MATa/MAT alpha cells and asporogenous MAT alpha/MAT alpha cells. A MATa/MAT alpha strain homozygous for a partial deletion of the SPS4 gene appeared, however, to be unaffected in its ability to form viable ascospores.

scholarly journals Secreted Aspartic Proteinase Family ofCandida tropicalis

2001 ◽  
Vol 69 (1) ◽  
pp. 405-412 ◽  
Author(s):  
Christophe Zaugg ◽  
Margarete Borg-von Zepelin ◽  
Utz Reichard ◽  
Dominique Sanglard ◽  
Michel Monod
Keyword(s):  
Southern Blotting ◽  
Genomic Library ◽  
Expression System ◽  
Methylotrophic Yeast ◽  
Sole Source ◽  
Gene Products ◽  
Related Gene ◽  
Recombinant Enzymes ◽  
Basic Level

ABSTRACT Medically important yeasts of the genus Candida secrete aspartic proteinases (Saps), which are of particular interest as virulence factors. Like Candida albicans, Candida tropicalis secretes in vitro one dominant Sap (Sapt1p) in a medium containing bovine serum albumin (BSA) as the sole source of nitrogen. Using the gene SAPT1 as a probe and under low-stringency hybridization conditions, three new closely related gene sequences, SAPT2 to SAPT4, encoding secreted proteinases were cloned from a C. tropicalis λEMBL3 genomic library. All bands identified by Southern blotting ofEcoRI-digested C. tropicalis genomic DNA withSAPT1 could be assigned to a specific SAP gene. Therefore, the SAPT gene family of C. tropicalis is likely to contain only four members. Interestingly, the SAPT2 and SAPT3 gene products, Sapt2p and Sapt3p, which have not yet been detected in C. tropicaliscultures in vitro, were produced as active recombinant enzymes with the methylotrophic yeast Pichia pastoris as an expression system. As expected, reverse transcriptase PCR experiments revealed a strong SAPT1 signal with RNA extracted from cells grown in BSA medium. However, a weak signal was obtained with all otherSAPT genes under several conditions tested, showing that these SAPT genes could be expressed at a basic level. Together, these experiments suggest that the gene products Sapt2p, Sapt3p, and Sapt4p could be produced under conditions yet to be described in vitro or during infection.

scholarly journals Functional expression and RNA binding analysis of the interferon-induced, double-stranded RNA-activated, 68,000-Mr protein kinase in a cell-free system.

1991 ◽  
Vol 11 (11) ◽  
pp. 5497-5505 ◽  
Author(s):  
M G Katze ◽  
M Wambach ◽  
M L Wong ◽  
M Garfinkel ◽  
E Meurs ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Expression System ◽  
In Vitro Translation ◽  
Initiation Factor ◽  
Alpha Subunit ◽  
Single Amino Acid ◽  
Free System

Eukaryotic viruses have devised numerous strategies to downregulate activity of the interferon-induced, double-stranded (dsRNA)-activated protein kinase (referred to as p68 on the basis of its Mr of 68,000 in human cells). Viruses must exert this control to avoid extensive phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF-2) by p68 and the resultant negative effects on protein synthesis initiation. To begin to define the molecular mechanisms underlying this regulation, we optimized expression of p68 in an in vitro transcription-translation system utilizing the full-length cDNA clone. The in vitro-expressed kinase was autophosphorylated in response to dsRNAs and heparin in a manner similar to that for the native p68 provided that the kinase inhibitor, 2-aminopurine, was present during the in vitro translation reaction. Further, the activated kinase efficiently phosphorylated its natural substrate, the alpha subunit of eIF-2. Binding experiments revealed that the expressed kinase complexed with the dsRNA activator, reovirus dsRNA, as well as the adenovirus-encoded inhibitor, VAI RNA. Interestingly, both the reovirus RNAs and VAI RNA also complexed with protein kinase molecules that lacked the carboxyl terminus and all catalytic domains. Deletion analysis confirmed that the p68 amino terminus contained critical determinants for reovirus dsRNA and VAI RNA binding. Further, reovirus dsRNA efficiently bound to, but failed to activate, p68 kinase molecules containing a single amino acid substitution in the invariant lysine 295 present in catalytic domain II. Taken together, these data demonstrate that this expression system permits a detailed mutagenic analysis of the regions of p68 required for interaction with virus-encoded activators and repressors.

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