scholarly journals A multicopy suppressor gene of the Saccharomyces cerevisiae G1 cell cycle mutant gene dbf4 encodes a protein kinase and is identified as CDC5.

1993 ◽  
Vol 13 (7) ◽  
pp. 4445-4457 ◽  
Author(s):  
K Kitada ◽  
A L Johnson ◽  
L H Johnston ◽  
A Sugino

We have isolated a multicopy suppressor of the temperature-sensitive growth phenotype of organisms carrying mutations of DBF4, a gene that is required for the initiation of chromosomal DNA replication in Saccharomyces cerevisiae and that interacts with the CDC7 protein kinase. Nucleotide sequence analysis of the suppressor gene, provisionally named MSD2, revealed an open reading frame encoding a protein with a calculated M(r) of 81,024, with amino acid sequence similarity to the catalytic domains of protein kinases. Both genetic linkage and complementation analyses indicated that MSD2 is identical to the cell division cycle gene CDC5. An activity that phosphorylated exogenously added casein was immunoprecipitated by antiserum against a TrpE-Cdc5 fusion protein from lysates of wild-type cells containing CDC5 on a multicopy plasmid but not of cells bearing a small deletion in the predicted protein kinase domain of CDC5 on the plasmid. Deletion of CDC5 was lethal and resulted in a dumbbell-shaped terminal morphology, with the nuclei almost divided but still connected. Consistent with the function at the G2/M boundary, the CDC5 transcript accumulated periodically during the cell cycle, peaking at the G2/M boundary. CDC5 on a multicopy plasmid also suppresses temperature-sensitive cdc15, cdc20, and dbf2 mutations which affect mitosis during the cell cycle.

1993 ◽  
Vol 13 (7) ◽  
pp. 4445-4457
Author(s):  
K Kitada ◽  
A L Johnson ◽  
L H Johnston ◽  
A Sugino

We have isolated a multicopy suppressor of the temperature-sensitive growth phenotype of organisms carrying mutations of DBF4, a gene that is required for the initiation of chromosomal DNA replication in Saccharomyces cerevisiae and that interacts with the CDC7 protein kinase. Nucleotide sequence analysis of the suppressor gene, provisionally named MSD2, revealed an open reading frame encoding a protein with a calculated M(r) of 81,024, with amino acid sequence similarity to the catalytic domains of protein kinases. Both genetic linkage and complementation analyses indicated that MSD2 is identical to the cell division cycle gene CDC5. An activity that phosphorylated exogenously added casein was immunoprecipitated by antiserum against a TrpE-Cdc5 fusion protein from lysates of wild-type cells containing CDC5 on a multicopy plasmid but not of cells bearing a small deletion in the predicted protein kinase domain of CDC5 on the plasmid. Deletion of CDC5 was lethal and resulted in a dumbbell-shaped terminal morphology, with the nuclei almost divided but still connected. Consistent with the function at the G2/M boundary, the CDC5 transcript accumulated periodically during the cell cycle, peaking at the G2/M boundary. CDC5 on a multicopy plasmid also suppresses temperature-sensitive cdc15, cdc20, and dbf2 mutations which affect mitosis during the cell cycle.


1993 ◽  
Vol 13 (7) ◽  
pp. 3872-3881
Author(s):  
F Estruch ◽  
M Carlson

The MSN2 gene was selected as a multicopy suppressor in a temperature-sensitive SNF1 protein kinase mutant of Saccharomyces cerevisiae. MSN2 encodes a Cys2His2 zinc finger protein related to the yeast MIG1 repressor and to mammalian early growth response and Wilms' tumor zinc finger proteins. Deletion of MSN2 caused no phenotype. A second similar zinc finger gene, MSN4, was isolated, and deletion of both genes caused phenotypic defects related to carbon utilization. Overexpression of the zinc finger regions was deleterious to growth. LexA-MSN2 and LexA-MSN4 fusion proteins functioned as strong transcriptional activators when bound to DNA. Functional roles of this zinc finger protein family are discussed.


1983 ◽  
Vol 3 (9) ◽  
pp. 1665-1669 ◽  
Author(s):  
M N Conrad ◽  
C S Newlon

DNA isolated from Saccharomyces cerevisiae strains carrying temperature-sensitive mutations in the CDC2 gene after incubation at the restrictive temperature contains multiple stably denatured regions 200 to 700 base pairs long. These regions are probably stabilized by a DNA-binding protein. They are found in both replicated and unreplicated portions of DNA molecules, suggesting that they are not an early stage in the initiation of DNA replication.


Genetics ◽  
1992 ◽  
Vol 131 (1) ◽  
pp. 21-29 ◽  
Author(s):  
K Kitada ◽  
L H Johnston ◽  
T Sugino ◽  
A Sugino

Abstract When present on a multicopy plasmid, a gene from a Saccharomyces cerevisiae genomic library suppresses the temperature-sensitive cdc7-1 mutation. The gene was identified as DBF4, which was previously isolated by complementation in dbf4-1 mutant cells and is required for the G1----S phase progression of the cell cycle. DBF4 has an open reading frame encoding 695 amino acid residues and the predicted molecular mass of the gene product is 80 kD. The suppression is allele-specific because a CDC7 deletion is not suppressed by DBF4. Suppression is mitosis-specific and the sporulation defect of cdc7 mutations is not suppressed by DBF4. Conversely, CDC7 on a multicopy plasmid suppresses the dbf4-1, -2, -3 and -4 mutations but not dbf4-5 and DBF4 deletion mutations. Furthermore, cdc7 mutations are incompatible with the temperature-sensitive dbf4 mutations. These results suggest that the CDC7 and DBF4 polypeptides interact directly or indirectly to permit initiation of yeast chromosome replication.


1993 ◽  
Vol 13 (7) ◽  
pp. 3872-3881 ◽  
Author(s):  
F Estruch ◽  
M Carlson

The MSN2 gene was selected as a multicopy suppressor in a temperature-sensitive SNF1 protein kinase mutant of Saccharomyces cerevisiae. MSN2 encodes a Cys2His2 zinc finger protein related to the yeast MIG1 repressor and to mammalian early growth response and Wilms' tumor zinc finger proteins. Deletion of MSN2 caused no phenotype. A second similar zinc finger gene, MSN4, was isolated, and deletion of both genes caused phenotypic defects related to carbon utilization. Overexpression of the zinc finger regions was deleterious to growth. LexA-MSN2 and LexA-MSN4 fusion proteins functioned as strong transcriptional activators when bound to DNA. Functional roles of this zinc finger protein family are discussed.


1983 ◽  
Vol 3 (9) ◽  
pp. 1665-1669
Author(s):  
M N Conrad ◽  
C S Newlon

DNA isolated from Saccharomyces cerevisiae strains carrying temperature-sensitive mutations in the CDC2 gene after incubation at the restrictive temperature contains multiple stably denatured regions 200 to 700 base pairs long. These regions are probably stabilized by a DNA-binding protein. They are found in both replicated and unreplicated portions of DNA molecules, suggesting that they are not an early stage in the initiation of DNA replication.


1986 ◽  
Vol 6 (5) ◽  
pp. 1590-1598
Author(s):  
M Patterson ◽  
R A Sclafani ◽  
W L Fangman ◽  
J Rosamond

The product of the CDC7 gene of Saccharomyces cerevisiae appears to have multiple roles in cellular physiology. It is required for the initiation of mitotic DNA synthesis. While it is not required for the initiation of meiotic DNA replication, it is necessary for genetic recombination during meiosis and for the formation of ascospores. It has also been implicated in an error-prone DNA repair pathway. Plasmids capable of complementing temperature-sensitive cdc7 mutations were isolated from libraries of yeast genomic DNA in the multicopy plasmid vectors YRp7 and YEp24. The complementing activity was localized within a 3.0-kilobase genomic DNA fragment. Genetic studies that included integration of the genomic insert at or near the CDC7 locus and marker rescue of four cdc7 alleles proved that the cloned fragment contains the yeast chromosomal CDC7 gene. The RNA transcript of CDC7 is about 1,700 nucleotides. Analysis of the nucleotide sequence of a 2.1-kilobase region of the cloned fragment revealed the presence of an open reading frame of 1,521 nucleotides that is presumed to encode the CDC7 protein. Depending on which of two possible ATG codons initiates translation, the calculated size of the CDC7 protein is 58.2 or 56 kilodaltons. Comparison of the predicted amino acid sequence of the CDC7 gene product with other known protein sequences suggests that CDC7 encodes a protein kinase.


1993 ◽  
Vol 13 (5) ◽  
pp. 3076-3083
Author(s):  
K Irie ◽  
M Takase ◽  
K S Lee ◽  
D E Levin ◽  
H Araki ◽  
...  

The PKC1 gene of Saccharomyces cerevisiae encodes a homolog of mammalian protein kinase C that is required for normal growth and division of yeast cells. We report here the isolation of the yeast MKK1 and MKK2 (for mitogen-activated protein [MAP] kinase-kinase) genes which, when overexpressed, suppress the cell lysis defect of a temperature-sensitive pkc1 mutant. The MKK genes encode protein kinases most similar to the STE7 product of S. cerevisiae, the byr1 product of Schizosaccharomyces pombe, and vertebrate MAP kinase-kinases. Deletion of either MKK gene alone did not cause any apparent phenotypic defects, but deletion of both MKK1 and MKK2 resulted in a temperature-sensitive cell lysis defect that was suppressed by osmotic stabilizers. This phenotypic defect is similar to that associated with deletion of the BCK1 gene, which is thought to function in the pathway mediated by PCK1. The BCK1 gene also encodes a predicted protein kinase. Overexpression of MKK1 suppressed the growth defect caused by deletion of BCK1, whereas an activated allele of BCK1 (BCK1-20) did not suppress the defect of the mkk1 mkk2 double disruption. Furthermore, overexpression of MPK1, which encodes a protein kinase closely related to vertebrate MAP kinases, suppressed the defect of the mkk1 mkk2 double mutant. These results suggest that MKK1 and MKK2 function in a signal transduction pathway involving the protein kinases encoded by PKC1, BCK1, and MPK1. Genetic epistasis experiments indicated that the site of action for MKK1 and MKK2 is between BCK1 and MPK1.


1991 ◽  
Vol 11 (11) ◽  
pp. 5710-5717
Author(s):  
E A Malone ◽  
C D Clark ◽  
A Chiang ◽  
F Winston

SPT16 was previously identified as a high-copy-number suppressor of delta insertion mutations in the 5' regions of the HIS4 and LYS2 genes of Saccharomyces cerevisiae. We have constructed null mutations in the SPT16 gene and have demonstrated that it is essential for growth. Temperature-sensitive-lethality spt16 alleles have been isolated and shown to be pleiotropic; at a temperature permissive for growth, spt16 mutations suppress delta insertion mutations, a deletion of the SUC2 upstream activating sequence, and mutations in trans-acting genes required for both SUC2 and Ty expression. In addition, SPT16 is identical to CDC68, a gene previously shown to be required for passage through the cell cycle control point START. However, at least some transcriptional effects caused by spt16 mutations are independent of arrest at START. These results and those in the accompanying paper (A. Rowley, R. A. Singer, and G. C. Johnston, Mol. Cell. Biol. 11:5718-5726, 1991) indicate that SPT16/CDC68 is required for normal transcription of many loci in S. cerevisiae.


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