scholarly journals Fip1 Regulates the Activity of Poly(A) Polymerase through Multiple Interactions

2001 ◽  
Vol 21 (6) ◽  
pp. 2026-2037 ◽  
Author(s):  
Steffen Helmling ◽  
Alexander Zhelkovsky ◽  
Claire L. Moore
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Rna Binding ◽  
Physiological Function ◽  
Regulatory Function ◽  
Functional Domains ◽  
Essential Component ◽  
C Terminus ◽  
Mrna Precursor ◽  
Multiple Interactions

ABSTRACT Fip1 is an essential component of the Saccharomyces cerevisiae polyadenylation machinery and the only protein known to interact directly with poly(A) polymerase (Pap1). Its association with Pap1 inhibits the extension of an oligo(A) primer by limiting access of the RNA substrate to the C-terminal RNA binding domain (C-RBD) of Pap1. We present here the identification of separate functional domains of Fip1. Amino acids 80 to 105 are required for binding to Pap1 and for the inhibition of Pap1 activity. This region is also essential for viability, suggesting that Fip1-mediated repression of Pap1 has a crucial physiological function. Amino acids 206 to 220 of Fip1 are needed for the interaction with the Yth1 subunit of the complex and for specific polyadenylation of the cleaved mRNA precursor. A third domain within amino acids 105 to 206 helps to limit RNA binding at the C-RBD of Pap1. Our data demonstrate that the C terminus of Fip1 is required to relieve the Fip1-mediated repression of Pap1 in specific polyadenylation. In the absence of this domain, Pap1 remains in an inhibited state. These findings show that Fip1 has a crucial regulatory function in the polyadenylation reaction by controlling the activity of poly(A) tail synthesis through multiple interactions within the polyadenylation complex.

Regulatory function of the Saccharomyces cerevisiae RAS C-terminus

1987 ◽  
Vol 7 (7) ◽  
pp. 2309-2315
Author(s):  
M S Marshall ◽  
J B Gibbs ◽  
E M Scolnick ◽  
I S Sigal
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Adenylate Cyclase ◽  
Attachment Site ◽  
Hydrolytic Activity ◽  
Regulatory Function ◽  
Coding Region ◽  
Activating Mutations ◽  
Terminal Domain ◽  
C Terminus ◽  
Type Gene

Activating mutations (valine 19 or leucine 68) were introduced into the Saccharomyces cerevisiae RAS1 and RAS2 genes. In addition, a deletion was introduced into the wild-type gene and into an activated RAS2 gene, removing the segment of the coding region for the unique C-terminal domain that lies between the N-terminal 174 residues and the penultimate 8-residue membrane attachment site. At low levels of expression, a dominant activated phenotype, characterized by low glycogen levels and poor sporulation efficiency, was observed for both full-length RAS1 and RAS2 variants having impaired GTP hydrolytic activity. Lethal CDC25 mutations were bypassed by the expression of mutant RAS1 or RAS2 proteins with activating amino acid substitutions, by expression of RAS2 proteins lacking the C-terminal domain, or by normal and oncogenic mammalian Harvey ras proteins. Biochemical measurements of adenylate cyclase in membrane preparations showed that the expression of RAS2 proteins lacking the C-terminal domain can restore adenylate cyclase activity to cdc25 membranes.

scholarly journals Saccharomyces cerevisiae SSB1 protein and its relationship to nucleolar RNA-binding proteins

1987 ◽  
Vol 7 (8) ◽  
pp. 2947-2955
Author(s):  
A Y Jong ◽  
M W Clark ◽  
M Gilbert ◽  
A Oehm ◽  
J L Campbell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Nucleic Acid ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Nucleic Acid Binding ◽  
Dna And Rna ◽  
C Terminus

To better define the function of Saccharomyces cerevisiae SSB1, an abundant single-stranded nucleic acid-binding protein, we determined the nucleotide sequence of the SSB1 gene and compared it with those of other proteins of known function. The amino acid sequence contains 293 amino acid residues and has an Mr of 32,853. There are several stretches of sequence characteristic of other eucaryotic single-stranded nucleic acid-binding proteins. At the amino terminus, residues 39 to 54 are highly homologous to a peptide in calf thymus UP1 and UP2 and a human heterogeneous nuclear ribonucleoprotein. Residues 125 to 162 constitute a fivefold tandem repeat of the sequence RGGFRG, the composition of which suggests a nucleic acid-binding site. Near the C terminus, residues 233 to 245 are homologous to several RNA-binding proteins. Of 18 C-terminal residues, 10 are acidic, a characteristic of the procaryotic single-stranded DNA-binding proteins and eucaryotic DNA- and RNA-binding proteins. In addition, examination of the subcellular distribution of SSB1 by immunofluorescence microscopy indicated that SSB1 is a nuclear protein, predominantly located in the nucleolus. Sequence homologies and the nucleolar localization make it likely that SSB1 functions in RNA metabolism in vivo, although an additional role in DNA metabolism cannot be excluded.

scholarly journals Functional domains of a negative regulatory protein, GAL80, of Saccharomyces cerevisiae.

1989 ◽  
Vol 9 (7) ◽  
pp. 3009-3017 ◽  
Author(s):  
Y Nogi ◽  
T Fukasawa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Regulatory Protein ◽  
Subcellular Fractionation ◽  
Functional Domains ◽  
Amino Acid Residues ◽  
Coding Region ◽  
Interaction Domain ◽  
Repression Domain

To study the functional domains of a transcriptional repressor encoded by the GAL80 gene of Saccharomyces cerevisiae, we constructed various deletion and insertion mutations in the GAL80 coding region and determined the ability of these mutations to repress synthesis of galactose-metabolizing enzymes as well as the capacity of the mutant proteins to respond to the inducer. Two regions, from amino acids 1 to 321 and from amino acids 341 to 423, in the total sequence of 435 amino acids were required for repression. The internal region from amino acids 321 to 340 played a role in the response to the inducer. The 12 amino acids at the carboxy terminus were dispensable for normal functioning of the GAL80 protein. Using indirect immunofluorescence and subcellular fractionation techniques, we also found that two distinct regions (amino acids 1 to 109 and 342 to 405) within the putative repression domain were capable of directing cytoplasmically synthesized Escherichia coli beta-galactosidase to the yeast nucleus. In addition, three gal80 mutations were mapped at amino acid residues 183, 298, and 310 in the domain required for repression. On the basis of these results, we suggest that the GAL80 protein consists of a repression domain located in two separate regions (amino acid residues 1 to 321 and 341 to 423) that are interrupted by an inducer interaction domain (residues 322 to 340) and two nuclear localization domains (1 to 109 and 342 to 405) that overlap the repression domains.

scholarly journals Stem-Loop Binding Protein Facilitates 3′-End Formation by Stabilizing U7 snRNP Binding to Histone Pre-mRNA

1999 ◽  
Vol 19 (5) ◽  
pp. 3561-3570 ◽  
Author(s):  
Zbigniew Dominski ◽  
Lian-Xing Zheng ◽  
Ricardo Sanchez ◽  
William F. Marzluff
Keyword(s):  
Amino Acids ◽  
Rna Binding ◽  
Binding Protein ◽  
Nuclear Extract ◽  
Stable Complex ◽  
Stem Loop ◽  
Terminal Domain ◽  
C Terminus ◽  
Loop Sequence ◽  
U7 Snrnp

ABSTRACT The 3′ end of histone mRNA is formed by an endonucleolytic cleavage of the primary transcript after a conserved stem-loop sequence. The cleavage reaction requires at least two trans-acting factors: the stem-loop binding protein (SLBP), which binds the stem-loop sequence, and the U7 snRNP that interacts with a sequence downstream from the cleavage site. Removal of SLBP from a nuclear extract abolishes 3′-end processing, and the addition of recombinant SLBP restores processing activity of the depleted extract. To determine the regions of human SLBP necessary for 3′ processing, various deletion mutants of the protein were tested for their ability to complement the SLBP-depleted extract. The entire N-terminal domain and the majority of the C-terminal domain of human SLBP are dispensable for processing. The minimal protein that efficiently supports cleavage of histone pre-mRNA consists of 93 amino acids containing the 73-amino-acid RNA-binding domain and 20 amino acids located immediately next to its C terminus. Replacement of these 20 residues with an unrelated sequence in the context of the full-length SLBP reduces processing >90%. Coimmunoprecipitation experiments with the anti-SLBP antibody demonstrated that SLBP and U7 snRNP form a stable complex only in the presence of pre-mRNA substrates containing a properly positioned U7 snRNP binding site. One role of SLBP is to stabilize the interaction of the histone pre-mRNA with U7 snRNP.

scholarly journals Vif is an auxiliary factor of the HIV-1 reverse transcriptase and facilitates abasic site bypass

2004 ◽  
Vol 383 (3) ◽  
pp. 475-482 ◽  
Author(s):  
Reynel CANCIO ◽  
Silvio SPADARI ◽  
Giovanni MAGA
Keyword(s):  
Amino Acids ◽  
Reverse Transcriptase ◽  
Rna Binding ◽  
Abasic Site ◽  
Association Rate ◽  
C Terminus ◽  
Synthesis Activity ◽  
Auxiliary Factor ◽  
Hiv 1 ◽  
Rna And Dna

The HIV-1 accessory protein Vif was found to modulate the RNA- and DNA-dependent DNA synthesis activity of the viral RT (reverse transcriptase) in two ways: (i) it stimulated the binding of the viral RT to the primer by increasing the association rate kcat/Km and by decreasing the thermodynamic barrier ΔH[ES] for complex fomation, and (ii) it increased the polymerization rate of HIV-1 RT. A Vif mutant lacking the final 56 amino acids at the C-terminus failed to stimulate the viral RT. On the other hand, another Vif mutant lacking the first 43 amino acids at the N-terminus, which are involved in RNA binding and interaction with the viral protease, was able to stimulate RT activity. In addition, Vif was found to promote the bypass of an abasic site by HIV-1 RT.

scholarly journals Sorting Signals within the Saccharomyces cerevisiae Sporulation-Specific Dityrosine Transporter, Dtr1p, C Terminus Promote Golgi-to-Prospore Membrane Transport

2008 ◽  
Vol 7 (10) ◽  
pp. 1674-1684 ◽  
Author(s):  
Masayo Morishita ◽  
JoAnne Engebrecht
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Plasma Membrane ◽  
Membrane Transport ◽  
Transmembrane Domain ◽  
Spore Wall ◽  
Bilayer Membrane ◽  
C Terminus ◽  
Prospore Membrane ◽  
Dividing Cells

ABSTRACT During sporulation in Saccharomyces cerevisiae, the dityrosine transporter Dtr1p, which is required for formation of the outermost layer of the spore wall, is specifically expressed and transported to the prospore membrane, a novel double-lipid-bilayer membrane. Dtr1p consists of 572 amino acids with predicted N- and C-terminal cytoplasmic extensions and 12 transmembrane domains. Dtr1p missing the largest internal cytoplasmic loop was trapped in the endoplasmic reticulum in both mitotically dividing cells and cells induced to sporulate. Deletion of the carboxyl 15 amino acids, but not the N-terminal extension of Dtr1p, resulted in a protein that failed to localize to the prospore membrane and was instead observed in cytoplasmic puncta. The puncta colocalized with a cis-Golgi marker, suggesting that Dtr1p missing the last 15 amino acids was trapped in an early Golgi compartment. Deletion of the C-terminal 10 amino acids resulted in a protein that localized to the prospore membrane with a delay and accumulated in cytoplasmic puncta that partially colocalized with a trans-Golgi marker. Both full-length Dtr1p and Dtr1p missing the last 10 amino acids expressed in vegetative cells localized to the plasma membrane and vacuoles, while Dtr1p deleted for the carboxyl-terminal 15 amino acids was observed only at vacuoles, suggesting that transport to the prospore membrane is mediated by distinct signals from those that specify plasma membrane localization. Transfer-of-function experiments revealed that both the carboxyl transmembrane domain and the C-terminal tail are important for Golgi complex-to-prospore membrane transport.

scholarly journals Tethered Sir3p nucleates silencing at telomeres and internal loci in Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (5) ◽  
pp. 2483-2495 ◽  
Author(s):  
A J Lustig ◽  
C Liu ◽  
C Zhang ◽  
J P Hanish
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Binding Sites ◽  
Associated Factors ◽  
Wild Type ◽  
Gain Of Function ◽  
Telomeric Silencing ◽  
C Terminus ◽  
Lexa Binding ◽  
In Cis

Rap1p binds to sites embedded within the Saccharomyces cerevisiae telomeric TG1-3 tract. Previous studies have led to the hypothesis that Rap1p may recruit Sir3p and Sir3p-associating factors to the telomere. To test this, we tethered Sir3p adjacent to the telomere via LexA binding sites in the rap1-17 mutant that truncates the Rap1p C-terminal 165 amino acids thought to contain sites for Sir3p association. Tethering of LexA-Sir3p adjacent to the telomere is sufficient to restore telomeric silencing, indicating that Sir3p can nucleate silencing at the telomere. Tethering of LexA-Sir3p or the LexA-Sir3p(N2O5) gain-of-function protein to a telomeric LexA site hyperrepresses an adjacent ADE2 gene in wild-type cells. Hence, Sir3p recruitment to the telomere is limiting in telomeric silencing. In addition, LexA-Sir3p(N2O5) hyperrepresses telomeric silencing when tethered to a subtelomeric site 3.6 kb from the telomeric tract. This hyperrepression is dependent on the C terminus of Rap1p, suggesting that subtelomeric LexA-Sir3p(N205) can interact with Rap1p-associated factors at the telomere. We also demonstrate that LexA-Sir3p or LexA-Sir3p(N205) tethered in cis with a short tract of telomeric TG1-3 sequences is sufficient to confer silencing at an internal chromosomal position. Internal silencing is enhanced in rap1-17 strains. We propose that sequestration of silencing factors at the telomere limits the efficiency of internal silencing.

scholarly journals Saccharomyces cerevisiae SSB1 protein and its relationship to nucleolar RNA-binding proteins.

1987 ◽  
Vol 7 (8) ◽  
pp. 2947-2955 ◽  
Author(s):  
A Y Jong ◽  
M W Clark ◽  
M Gilbert ◽  
A Oehm ◽  
J L Campbell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Nucleic Acid ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Nucleic Acid Binding ◽  
Dna And Rna ◽  
C Terminus

To better define the function of Saccharomyces cerevisiae SSB1, an abundant single-stranded nucleic acid-binding protein, we determined the nucleotide sequence of the SSB1 gene and compared it with those of other proteins of known function. The amino acid sequence contains 293 amino acid residues and has an Mr of 32,853. There are several stretches of sequence characteristic of other eucaryotic single-stranded nucleic acid-binding proteins. At the amino terminus, residues 39 to 54 are highly homologous to a peptide in calf thymus UP1 and UP2 and a human heterogeneous nuclear ribonucleoprotein. Residues 125 to 162 constitute a fivefold tandem repeat of the sequence RGGFRG, the composition of which suggests a nucleic acid-binding site. Near the C terminus, residues 233 to 245 are homologous to several RNA-binding proteins. Of 18 C-terminal residues, 10 are acidic, a characteristic of the procaryotic single-stranded DNA-binding proteins and eucaryotic DNA- and RNA-binding proteins. In addition, examination of the subcellular distribution of SSB1 by immunofluorescence microscopy indicated that SSB1 is a nuclear protein, predominantly located in the nucleolus. Sequence homologies and the nucleolar localization make it likely that SSB1 functions in RNA metabolism in vivo, although an additional role in DNA metabolism cannot be excluded.

scholarly journals Regulatory function of the Saccharomyces cerevisiae RAS C-terminus.

1987 ◽  
Vol 7 (7) ◽  
pp. 2309-2315 ◽  
Author(s):  
M S Marshall ◽  
J B Gibbs ◽  
E M Scolnick ◽  
I S Sigal
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Adenylate Cyclase ◽  
Attachment Site ◽  
Hydrolytic Activity ◽  
Regulatory Function ◽  
Coding Region ◽  
Activating Mutations ◽  
Terminal Domain ◽  
C Terminus ◽  
Type Gene

Activating mutations (valine 19 or leucine 68) were introduced into the Saccharomyces cerevisiae RAS1 and RAS2 genes. In addition, a deletion was introduced into the wild-type gene and into an activated RAS2 gene, removing the segment of the coding region for the unique C-terminal domain that lies between the N-terminal 174 residues and the penultimate 8-residue membrane attachment site. At low levels of expression, a dominant activated phenotype, characterized by low glycogen levels and poor sporulation efficiency, was observed for both full-length RAS1 and RAS2 variants having impaired GTP hydrolytic activity. Lethal CDC25 mutations were bypassed by the expression of mutant RAS1 or RAS2 proteins with activating amino acid substitutions, by expression of RAS2 proteins lacking the C-terminal domain, or by normal and oncogenic mammalian Harvey ras proteins. Biochemical measurements of adenylate cyclase in membrane preparations showed that the expression of RAS2 proteins lacking the C-terminal domain can restore adenylate cyclase activity to cdc25 membranes.

scholarly journals The pentafunctional arom enzyme of Saccharomyces cerevisiae is a mosaic of monofunctional domains

1987 ◽  
Vol 246 (2) ◽  
pp. 375-386 ◽  
Author(s):  
K Duncan ◽  
R M Edwards ◽  
J R Coggins
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Nucleotide Sequence ◽  
Protein Sequence ◽  
Polypeptide Chain ◽  
Functional Domains ◽  
E Coli ◽  
Multifunctional Enzyme ◽  
Functional Regions

The nucleotide sequence of the Saccharomyces cerevisiae ARO1 gene which encodes the arom multifunctional enzyme has been determined. The protein sequence deduced for the pentafunctional arom polypeptide is 1588 amino acids in length and has a calculated Mr of 174555. Functional regions within the polypeptide chain have been identified by comparison with the sequences of the five monofunctional Escherichia coli enzymes whose activities correspond with those of the arom multifunctional enzyme. The observed homologies demonstrate that the arom polypeptide is a mosaic of functional domains and are consistent with the hypothesis that the ARO1 gene evolved by the linking of ancestral E. coli-like genes.

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