Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1617-4623
    Keywords: Recombinant DNA ; Methionine metabolism ; Negative control ; Regulatory regions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Saccharomyces cerevisiae, the expression of several genes implicated in methionine biosynthesis is coregulated by a specific negative control. To elucidate the molecular basis of this regulation, we have cloned two of these genes, MET3 and MET25. The sequence of MET25 has already been determined (Kerjan et al. 1986). Here, we report the nucleotide sequence of the MET3 gene along with its 5′ and 3′ flanking regions. Plasmids bearing different deletions upstream of the transcribed region of MET3 were constructed. They were introduced into yeast cells and tested for their ability to complement met3 mutations and to respond to regulation by exogenous methionine. The regulatory region was located within a 100 bp region. The sequence of this regulatory region was compared with that of MET25. A short common sequence which occurs 250–280 bp upstream of the translation initiation codon of the gene was found. This sequence is a good candidate for the cis-acting regulatory element.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mutants requiring S-adenosyl methionine (SAM) for growth have been selected in Saccharomyces cerevisiae. Two classes of mutants have been found. One class corresponds to the simultaneous occurrence of mutations at two unlinked loci SAM1 and SAM2 and presents a strict SAM requirement for growth on any medium. The second class corresponds to special single mutations in the gene SAM2 which lead to a residual growth on minimal medium but to normal growth on SAM supplemented medium or on a complex medium like YPGA not containing any SAM. These genetic data can be taken as an indication that Saccharomyces cerevisiae possesses two isoenzymatic methionine adenosyl transferases (MAT). In addition, SAM1 and SAM2 loci have been identified respectively with the ETH-10 and ETH2 loci previously described. Biochemical evidences corroborate the genetic results. Two MAT activities can be dissociated in a wild type extract (MATI and MATII) by DEAE cellulose chromatography. Mutations at the SAM1 locus lead to the absence or to the modification of MATII whereas mutations at the SAM2 locus lead to the absence or to the modification of MATI. Moreover, some of our results seem to show that MATI and MATII are associated in vivo.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 182 (1981), S. 65-69 
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Saccharomyces cerevisiae either of the two genes SAM1 and SAM2 is able to produce a functional methionine adenosyl transferase (MATI and MATII). In a wild-type strain, MATI and MATII are present in dimeric forms: MATI-MATI, MATII-MATII and perhaps MATI-MATII. A hypothesis is presented to explain the possible role of these different forms of methionine adenosyl transferase in S. cerevisiae.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The lysA gene of Escherichia coli has been cloned from a λ transducing phage on various plasmids, present in different copy numbers in bacterial cells. Synthesis of the product of this gene, diaminopimelate (DAP)-decarboxylase, and its regulation have been studied. Expression does not follow a simple gene dosage effect, maximal expression already being obtained with a six-copy plasmid. This result suggests that either a positive or an autogenous regulatory mechanism is involved. We also used one of the hybrid plasmids to look for expression of the bacterial lysA gene in Saccharomyces cerevisiae. The results indicate that the product of the E. coli gene is not actively translated in yeast.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1617-4623
    Keywords: Methionine metabolism ; Gene complementation ; MET25 gene ; Sulphydrylase ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We cloned the MET17 gene of Saccharomyces cerevisiae by functional complementation after transformation of a yeast met17 mutant. Restriction mapping and nucleotide sequencing of the MET17 clones revealed that these were from the same genomic region as clones isolated previously and shown to contain the MET25 gene encoding the enzyme O-acetylhomoserine, O-acetylserine sulphydrylase (OAH-OAS sulphydrylase). Transformation studies with MET25 clones showed that the MET17 and MET25 functions were both endoced in a single transcription unit. We conclude that met17 and met25 are both mutations in the structural gene for the OAH-OAS sulphydrylase subunit and that each affects a different fuctional domain of the enzyme allowing subunit complementation in the met17xmet25 diploid. Enzyme assays indicated that the diploid, although not requiring methionine, had a low OAH-OAS sulphydrylase activity (10% of wild type). This is consistent with MET17 and MET25 being the same gene. We found that both met17 and met25 mutants were devoid of 3′ phospho-adenosine 5′ phospho-sulphite (PAPS) reductase activity and that this activity was fully restored in the met17xmet25 diploid. The possible interactions between OAH-OAS sulphydrylase and PAPS reductase are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 200 (1985), S. 407-414 
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The MET25 gene of Saccharomyces cerevisiae was cloned by functional complementation after transformation of a yeast met25 mutant. Subcloning of the DNA fragment bearing MET25 located the gene on a 2.3 kb region. The gene was formally identified by integration at the chromosomal MET25 locus. The cloned MET25 gene was used as a probe to measure the MET25 messenger RNA in a wild-type strain grown under conditions which promoted or failed to promote repression of MET25 expression. It was found that, under repression conditions, MET25 messenger RNA was reduced tenfold when compared with non-repression conditions. This suggests that the expression of MET25 is regulated transcriptionally. The direction of transcription, the size of the transcript and the position of the transcribed part of the gene were determined. Deletion mapping of the regulatory region was carried out. Deleted plasmids were introduced back into yeast cells and tested for their ability to complement met25 mutations and to promote regulation of expression of the MET25 gene by exogenous methionine. By this method the regulatory region was found to be confined to a 130 bp region.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...