scholarly journals Preliminary characterization of the transcriptional and translational products of the Saccharomyces cerevisiae cell division cycle gene CDC28.

1982 ◽  
Vol 2 (4) ◽  
pp. 412-425 ◽  
Author(s):  
S I Reed ◽  
J Ferguson ◽  
J C Groppe

The CDC28 gene was subcloned from a plasmid containing a 6.5-kilobase-pair segment of Saccharomyces cerevisiae DNA YRp7(CDC28-3) by partial digestion with Sau3A and insertion of the resulting fragments into the BamHI sites of YRp7 and pRC1. Recombinant plasmids were obtained containing inserts of 4.4 and 3.1 kilobase pairs which were capable of complementing a cdc28(ts) mutation. R-loop analysis indicated that each yeast insert contained two RNA coding regions of about 0.8 and 1.0 kilobase pairs, respectively. In vitro mutagenesis experiments suggested that the smaller coding region corresponded to the CDC28 gene. When cellular polyadenylic acid-containing RNA, separated by agarose gel electrophoresis after denaturation with glyoxal and transferred to nitrocellulose membrane, was reacted with labeled DNA from the smaller coding region, and RNA species of about 1 kilobase in length was detected. Presumably, the discrepancy in size between the R-loop and electrophoretic determinations is due to a segment of polyadenylic acid which is excluded from the R-loops. By using hybridization of the histone H2B mRNAs to an appropriate probe as a previously determined standards, it was possible to estimate the number of CDC28 mRNA copies per haploid cell as between 6 and 12 molecules. Hybrid release translation performed on the CDC29 mRNA directed the synthesis of a polypeptide of 27,000 daltons, as determined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. This polypeptide was not synthesized when mRNA prepared from a cdc28 nonsense mutant was translated in a parallel fashion. However, if the RNA from a cell containing the CDC28 gene on a plasmid maintained at a high copy number was translated, the amount of in vitro product was amplified fivefold.

1982 ◽  
Vol 2 (4) ◽  
pp. 412-425
Author(s):  
S I Reed ◽  
J Ferguson ◽  
J C Groppe

The CDC28 gene was subcloned from a plasmid containing a 6.5-kilobase-pair segment of Saccharomyces cerevisiae DNA YRp7(CDC28-3) by partial digestion with Sau3A and insertion of the resulting fragments into the BamHI sites of YRp7 and pRC1. Recombinant plasmids were obtained containing inserts of 4.4 and 3.1 kilobase pairs which were capable of complementing a cdc28(ts) mutation. R-loop analysis indicated that each yeast insert contained two RNA coding regions of about 0.8 and 1.0 kilobase pairs, respectively. In vitro mutagenesis experiments suggested that the smaller coding region corresponded to the CDC28 gene. When cellular polyadenylic acid-containing RNA, separated by agarose gel electrophoresis after denaturation with glyoxal and transferred to nitrocellulose membrane, was reacted with labeled DNA from the smaller coding region, and RNA species of about 1 kilobase in length was detected. Presumably, the discrepancy in size between the R-loop and electrophoretic determinations is due to a segment of polyadenylic acid which is excluded from the R-loops. By using hybridization of the histone H2B mRNAs to an appropriate probe as a previously determined standards, it was possible to estimate the number of CDC28 mRNA copies per haploid cell as between 6 and 12 molecules. Hybrid release translation performed on the CDC29 mRNA directed the synthesis of a polypeptide of 27,000 daltons, as determined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. This polypeptide was not synthesized when mRNA prepared from a cdc28 nonsense mutant was translated in a parallel fashion. However, if the RNA from a cell containing the CDC28 gene on a plasmid maintained at a high copy number was translated, the amount of in vitro product was amplified fivefold.


1977 ◽  
Vol 163 (2) ◽  
pp. 369-378 ◽  
Author(s):  
P R Dunkley ◽  
H Holmes ◽  
R Rodnight

Synaptic-membrane fragments from ox cerebral cortex contain basal and cyclic AMP-stimulated protein kinase(s) that transfer 32P from [gamma-32P]ATP to hydroxyl groups of serine and threonine residues in membrane-protein substrates. In the present work, labelled membrane fragments were partitioned into soluble and insoluble fractions with Triton X-100, Nonidet P. 40, sodium deoxycholate and urea, and the distribution of 32P-labelled protein in the fractions was determined by polyacrylamide-gel electrophoresis and radioautography. A high percentage of phosphorylated protein sustrates remained insoluble, including those whose phosphorylation was most highly stimulated by cyclic AMP. Whole membrane fragments and samples prepared by detergent extraction were fractionated on Sepharose 6B columns in the presence of low concentrations of sodium dodecyl sulphate and pooled fractions were analysed by polyacrylamide-gel electrophoresis and radioautography. Phosphorylated proteins were fractionated on the basis of their molecular weight, but homogeneous protein was not obtained. The results are discussed in relation to the techniques used and the results obtained in other laboratories.


1985 ◽  
Vol 58 (6) ◽  
pp. 2091-2095 ◽  
Author(s):  
T. E. Weaver ◽  
J. A. Whitsett ◽  
W. M. Hull ◽  
G. Ross

Surfactant-associated glycoproteins A were identified by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of crude surfactant from canine alveolar lavage: an unglycosylated form (protein A1), 27,000–28,000 daltons; glycoprotein A2, 32,000–34,000 daltons; and glycoprotein A3, 37,000–38,000 daltons; pH at isoelectric point (pI) 4.5–5.0. Glycoproteins A2 and A3 were electroeluted and used to prepare a monospecific antiserum that identified proteins A1, A2, and A3 in immunoblots of crude surfactant obtained from dog lung lavage. This antiserum precipitated several proteins from in vitro translated canine lung poly(A)+ mRNA; proteins of 27,000 daltons, pI 5.0, and 28,000 daltons, pI 4.8–5.0, which precisely comigrated with proteins A1 from canine surfactant. Cotranslational processing of the primary translation products by canine pancreatic microsomal membranes resulted in larger proteins of 31,000–34,000 daltons, pI 4.8–5.0. Treatment of these processed forms of glycoprotein A with endoglycosidase F, to remove N-linked carbohydrate, resulted in proteins of 27,000–28,000 daltons which precisely comigrated with surfactant protein A1. These observations demonstrate that the polypeptide precursors to the glycoproteins A complex are extensively modified by addition of asparagine N-linked complex carbohydrate and are subsequently secreted as glycoproteins A2 and A3.


1978 ◽  
Vol 175 (3) ◽  
pp. 1079-1087 ◽  
Author(s):  
H Villarroya ◽  
J Williams ◽  
P Dey ◽  
S Villarroya ◽  
F Petek

Two beta-mannanases (beta-mannosidases, EC 3.2.1.25) purified from the germinated seeds of Trifolium repens by a procedure that included chromatography on hydroxyapatite, gel filtration on acrylamide/agarose (Ultragel 5/4) and preparative polyacrylamide-gel-electrophoresis. The final purification step completely resolved two beta-mannanases with distinct specificities, which were termed beta-mannanase I and beta-mannanase II. beta-Mannanase I was purified 1400-fold and beta-mannanase II 1000-fold. The purified enzymes showed a single protein band when examined by polyacrylamide-gel disc electrophoresis. beta-Mannanase I, apparent mol.wt. 43 000, accounted for 49% of the total activity recovered from the final step of purification. beta-Mannanase II, apparent mol.wt. 38 000, accounted for the remaining 51% of activity. Molecular-weight determinations were by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and by the electrophoretic method of Hendrick & Smith [(1968) Arch. Biochem. Biophys. 126, 155-164]. The substrate specificities of both enzymes were examined with the galactomannans of T. repens and of Medicago sativa, as well as with manno-oligosaccharides. The pH optimum was between pH 5.1 and 5.6 for both enzymes.


1992 ◽  
Vol 8 (3) ◽  
pp. 183-191 ◽  
Author(s):  
C. Arámburo ◽  
J. L. Montiel ◽  
J. A. Proudman ◽  
L. R. Berghman ◽  
C. G. Scanes

ABSTRACT To determine whether GH and prolactin could be phosphorylated, turkey GH, chicken GH, chicken prolactin and turkey prolactin were incubated in vitro with the catalytic subunit of protein kinase A and [γ-32P]ATP. Phosphorylation was assessed after sodium dodecyl sulphate-polyacrylamide gel electrophoresis, Western blotting and autoradiography. Polyacrylamide electrophoresis showed that both purified native chicken GH and turkey GH were phosphorylated under the conditions employed. However, the glycosylated variant of chicken GH did not appear to be labelled. Chicken prolactin, turkey prolactin and the glycosylated variant of turkey prolactin were all intensely phosphorylated by protein kinase A. Ovine and rat prolactins could also be phosphorylated by protein kinase A. The phosphate content of different native prolactin (turkey, ovine and rat) and GH (ovine and chicken) preparations was also determined and found to be significant. Chicken pituitary cells in primary culture incorporated P in GH- and prolactin-like bands isolated by non-denaturing polyacrylamide gel electrophoresis, and this was stimulated by phorbol myristate acetate. Phosphorylation of GH and prolactin may thus explain some of the charge heterogeneity of these hormones.


1979 ◽  
Vol 184 (2) ◽  
pp. 261-267 ◽  
Author(s):  
R K Craig ◽  
P A J Perera ◽  
A Mellor ◽  
A E Smith

1. Guinea-pig caseins synthesized in a mRNA-directed wheat-germ cell-free protein-synthesizing system represent the primary translation products, even though they appear to be of lower molecular weight when analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis in parallel with caseins isolated from guinea-pig milk. 2. Identification of the N-terminal dipeptide of the primary translational product of caseins A, B and C and alpha-lactalbumin showed that all shared a common sequence, which was identified as either Met-Arg or Met-Lys. 3. Procedures utilizing methionyl-tRNAfMet or methionyl-tRNAMet in the presence or absence of microsomal membranes during translation provide a rapid method of distinguishing between N-terminal processing of peptides synthesized in vitro and other post-translational modifications (glycosylation, phosphorylation), which also result in a change in mobility of peptides when analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 4. The results demonstrate that guinea-pig caseins, in common with most other secretory proteins, are synthesized with transient N-terminal ‘signal’-peptide extensions, which are cleaved during synthesis in the presence of microsomal membranes.


1976 ◽  
Vol 156 (3) ◽  
pp. 619-626 ◽  
Author(s):  
S M Tilghman ◽  
L M Fisher ◽  
L Reshef ◽  
F J Ballard ◽  
R W Hanson

1. mRNA was extracted from the livers of starved rats and incubated in a heterologous cell-free protein-synthesizing system derived from rabbit reticulocytes. The presence of newly synthesized phosphoenolpyruvate carboxykinase (GTP) was detected by immunoprecipitation with a specific antibody to the enzyme and analysis by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 2. The synthesis of the enzyme was dependent on the addition of rat liver RNA, whereas RNA isolated from rat spleen was inactive. If ovalbumin and anti-ovalbumin were used to form the immunoprecipitates, no radioactivity that migrated as phosphoenolpyruvate carboxykinase was detected. 3. The optimal concentrations of magnesium acetate and KCl for phosphoenolpyruvate carboxykinase synthesis were determined. 4. When polyribosomal RNA was separated by sucrose-gradient centrifugation, phosphoenolpyruvate carboxykinase mRNA migrated between 20 and 26 S in keeping with the high mol. wt. of the protein (85 000). 5. The presence of poly(A) in phosphoenolpyruvate carboxykinase mRNA was suggested by retention of mRNA activity on oligo(dT)-cellulose columns. 6. It was concluded that the cell-free synthesis of phosphoenolpyruvate carboxykinase can serve as a bioassay for intracellular phosphoenolpyruvate carboxykinase mRNA.


1983 ◽  
Vol 214 (3) ◽  
pp. 943-950 ◽  
Author(s):  
F van der Mark ◽  
W van den Briel ◽  
H G Huisman

Evidence is presented that French-bean (Phaseolus vulgaris) seed ferritin is composed of one type of subunit with an apparent Mr of 26500. In normal and iron-loaded leaf tissues it is detected immunologically with an antiserum raised against purified bean seed ferritin and migrates in SDS (sodium dodecyl sulphate)/polyacrylamide-gel electrophoresis with the same mobility as the bean seed ferritin subunit. The biosynthetic pathway of ferritin in normal and iron-loaded leaves was investigated. RNA was extracted, fractionated into polyadenylated RNA and translated in a cell-free rabbit reticulocyte lysate and a wheat-germ-extract system. The products were identified by SDS/polyacrylamide-gel electrophoresis after indirect immunoprecipitation. In all cases the ferritin product had an Mr 5000 higher than that of the native subunit. Uptake and processing of the precursor form of ferritin from iron-loaded leaves by intact chloroplasts was demonstrated. This indicates that, in iron-loaded leaves, ferritin acts as a chloroplast protein. We propose that the ferritin precursor in normal leaves follows the same biosynthetic pathway. This suggests that the iron-buffering function of ferritin in plants takes place in the chloroplast and that non-functional cellular iron will accumulate in this cell organelle.


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