Binding of the Replication Terminator Protein Fob1p to the Ter Sites of Yeast Causes Polar Fork Arrest

Fob1p protein has been implicated in the termination of replication forks at the two tandem termini present in the non-transcribed spacer region located between the sequences encoding the 35 S and the 5 S RNAs of Saccharomyces cerevisiae. However, the biochemistry and mode of action of this protein were previously unknown. We have purified the Fob1p protein to near-homogeneity, and we developed a novel technique to show that it binds specifically to the Ter1 and Ter2 sequences. Interestingly, the two sequences share no detectable homology. We present two lines of evidence showing that the interaction of the Fob1p with the Ter sites causes replication termination. First, a mutant of FOB1, L104S that significantly reduced the binding of the mutant form of the protein to the tandem Ter sites, also failed to promote replication termination in vivo. The mutant did not diminish nucleolar transport, and interaction of the mutant form of Fob1p with itself and with another protein encoded in the locus YDR026C suggested that the mutation did not cause global misfolding of the protein. Second, DNA site mutations in the Ter sequences that separately and specifically abolished replication fork arrest at Ter1 or Ter2 also eliminated sequence-specific binding of the Fob1p to the two sites. The work presented here definitively established Ter DNA-Fob1p interaction as an important step in fork arrest. Fob1p protein has been implicated in the termination of replication forks at the two tandem termini present in the non-transcribed spacer region located between the sequences encoding the 35 S and the 5 S RNAs of Saccharomyces cerevisiae. However, the biochemistry and mode of action of this protein were previously unknown. We have purified the Fob1p protein to near-homogeneity, and we developed a novel technique to show that it binds specifically to the Ter1 and Ter2 sequences. Interestingly, the two sequences share no detectable homology. We present two lines of evidence showing that the interaction of the Fob1p with the Ter sites causes replication termination. First, a mutant of FOB1, L104S that significantly reduced the binding of the mutant form of the protein to the tandem Ter sites, also failed to promote replication termination in vivo. The mutant did not diminish nucleolar transport, and interaction of the mutant form of Fob1p with itself and with another protein encoded in the locus YDR026C suggested that the mutation did not cause global misfolding of the protein. Second, DNA site mutations in the Ter sequences that separately and specifically abolished replication fork arrest at Ter1 or Ter2 also eliminated sequence-specific binding of the Fob1p to the two sites. The work presented here definitively established Ter DNA-Fob1p interaction as an important step in fork arrest. DNA replication in many prokaryotes is often terminated at sequence-specific replication termini (Ter sites). Replication terminator proteins specifically bind to the Ter sites and arrest forks in an orientation-specific mode with respect to the replication origins (1.Bastia D. Mohanty B.K. DePamphilis M. DNA Replication in Eukaryotic Cells. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY1996: 177-215Google Scholar). In many eukaryotes, although every replicon in the multiorigin chromosomes does not have specific Ter sites, such sites are present in the nontranscribed spacer sequences in the rDNA from yeast to man (1.Bastia D. Mohanty B.K. DePamphilis M. DNA Replication in Eukaryotic Cells. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY1996: 177-215Google Scholar, 2.Rothstein R. Michel B. Gangloff S. Genes Dev. 2000; 14: 1-10Crossref PubMed Google Scholar). In Escherichia coli and Bacillus subtilis, the Ter sites bind to replication termination proteins, called Tus and RTP, respectively, that are contrahelicases (3.Khatri G.S. MacAllister T. Sista P. Bastia D. Cell. 1989; 59: 667-674Abstract Full Text PDF PubMed Scopus (126) Google Scholar, 4.Lee E.H. Kornberg A. Hidaka M. Kobayashi T. Horiuchi T. Proc. Natl. Acad. Sci. U. S. A. 1989; 86: 9104-9108Crossref PubMed Scopus (114) Google Scholar) and impede replication fork movement not only by binding to the Ter sites but also by protein-protein interaction between the helicase and the terminator protein (5.Mulugu S. Potnis A. Shamsuzzaman Taylor J. Alexander K. Bastia D. Proc. Natl. Acad. Sci. U. S. A. 2001; 98: 9569-9574Crossref PubMed Scopus (55) Google Scholar). The rDNAs of Saccharomyces cerevisiae (6.Brewer B.J. Lockshon D. Fangman W. Cell. 1992; 71: 267-271Abstract Full Text PDF PubMed Scopus (209) Google Scholar, 7.Ward T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar), Schizosaccharomyces pombe (8.Sanchez J.A. Kim S.M. Huberman J.A. Exp. Cell Res. 1998; 238: 220-230Crossref PubMed Scopus (69) Google Scholar), Xenopus (9.Wisendanger B. Lucchini R. Koller T. Sogo J.M. Nucleic Acids Res. 1994; 22: 5038-5046Crossref PubMed Scopus (59) Google Scholar), mouse (10.Lopez-Estrano C. Schvartzman J.B. Krimer D.B. Hernandez P. J. Mol. Biol. 1998; 277: 249-256Crossref PubMed Scopus (51) Google Scholar), pea (11.Lopez-Estrano C. Schvartzman J.B. Krimer D.B. Hernandez P. Plant Mol. Biol. 1999; 40: 99-110Crossref PubMed Scopus (27) Google Scholar), and humans (12.Little R.D. Platt T.H. Schildkraut C.L. Mol. Cell. Biol. 1993; 13: 6600-6613Crossref PubMed Scopus (208) Google Scholar) have similar replication fork arrest systems located in their nontranscribed spacer elements. In S. pombe, replication fork arrest has been to at and the locus Cell. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar, 1999; PubMed Scopus (114) Google Scholar, S. J. 22: PubMed Scopus Google Scholar). The rDNA locus of S. cerevisiae of tandem of rDNA present in of the rDNA of a 35 S and a 5 S that in nontranscribed spacer called an of replication called tandem is located between the encoding the 35 S and the 5 S RNAs (6.Brewer B.J. Lockshon D. Fangman W. Cell. 1992; 71: 267-271Abstract Full Text PDF PubMed Scopus (209) Google Scholar, Huberman J.A. Mol. Cell. Biol. PubMed Scopus Google Scholar). The two replication forks at the The fork the 35 S rDNA in the as that of it the fork from the the the 5 S is at two Ter sites located in the nontranscribed spacer called and is from the 35 S The two Ter sites as replication fork or located in arrest replication forks in an (6.Brewer B.J. Lockshon D. Fangman W. Cell. 1992; 71: 267-271Abstract Full Text PDF PubMed Scopus (209) Google Scholar, 7.Ward T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar). The Ter1 and Ter2 sites are from by a and by DNA between their T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar). The Ter sites in prokaryotes and are R. Michel B. Gangloff S. Genes Dev. 2000; 14: 1-10Crossref PubMed Google Scholar). The yeast rDNA also a that of two called and that the and The region the tandem Ter sites. The and of between sequences at sites in a R.L. G.S. Cell. Full Text PDF PubMed Scopus Google Scholar, K. Keil R.L. G.S. Cell. Full Text PDF PubMed Scopus Google Scholar, Keil R.L. PubMed Google Scholar, G.S. Keil R.L. PubMed Google Scholar). of Ter sites in the that of the in the as not only the K. Keil R.L. G.S. Cell. Full Text PDF PubMed Scopus Google Scholar, Keil R.L. PubMed Google Scholar) but also fork arrest T. Horiuchi T. Genes Cells. PubMed Scopus (209) Google Scholar). has been developed to mutations in that and this technique has in the of that are in the Keil R.L. PubMed Google Scholar, Keil R.L. PubMed Google Scholar). The such a and by to in fork arrest at the Ter sites of rDNA T. Horiuchi T. Genes Cells. PubMed Scopus (209) Google Scholar). also a in rDNA and Prusty R. M. P. Keil R.L. Mol. Cell. 1999; Full Text Full Text PDF Scopus Google Scholar) and in and of rDNA T. M. Horiuchi T. Genes Dev. 1998; PubMed Scopus Google Scholar, K. Horiuchi T. Genes Cells. PubMed Scopus Google Scholar, Horiuchi T. Kobayashi T. Genes Dev. PubMed Scopus Google Scholar). of have been by in is and in replication termination. In the present we the of of and of the and the mutant of the protein in yeast to We show that Fob1p protein specifically binds to the Ter1 and Ter2 sites. We present two lines of evidence in of the that interaction of Fob1p with the Ter1 and Ter2 sites causes replication termination. First, we show that mutation in the locus that significantly the DNA binding of the encoded protein also the of the protein to arrest replication forks in vivo. Second, mutations at Ter1 and Ter2 sites that separately replication termination at sites also binding of Fob1p to the two sequences. the we that interaction of Fob1p with Ter sites a that replication forks in an orientation-specific with respect to the yeast are and from Keil R.L. PubMed Google Scholar). The mutant form of in as in and from a by of and coli and were as and S. 1989; PubMed Scopus Google Scholar). the in and the or by a by and tandem the site by from the B. M. B. 2001; PubMed Scopus Google Scholar) and as a at the of the in the the and the by A. A. A. P. 1998; 14: PubMed Scopus Google Scholar) and to the as Keil R.L. PubMed Google Scholar). The or and their the or were and or and and the of by with with and in the of and The were with a or or and or The that failed to were to the were from the and coli to and the The from coli were to the of and to the as from DNA by and at the with or and and to the by from the A. A. R. P. 1994; PubMed Scopus Google Scholar). The the by the of by with and and the or to the by and by to of replication fork the and and their or were the yeast P. J. PubMed Google Scholar) and or and the were by in DNA and DNA from yeast in to Cell DNA and were as previously B.J. Fangman W.L. Cell. Full Text PDF PubMed Scopus Google Scholar). The DNA to and as B.K. T. Bastia D. J. PubMed Scopus Google Scholar). of of the of with and to at and the were 5 and were and in of a of and the of were to the and the were in a by the to and the with between to The in a at and in a at in a and the to the to and it in the at The in a of and and to that of 5 of were with and the to the at The a and the were with of by of The protein with 5 of 5 of with of The the Fob1p protein were and a in a The with of and with a of to The Fob1p protein were and to of The were with of and of Fob1p protein with and reduced The in a of by binding to of with of by with of and with of and were of DNA protein were in of and The were in a and as The to of as in and with C. of were DNA binding as we have of this protein with that DNA Fob1p DNA with or and the were by S. Ter by with and the sequences of are The and the Ter were and The were separately and also of and and their mutant were as of and with of the in the of and The in and the DNA were a of have been in of the sequences are in the and sequences are DNA the protein to of DNA in the of 5 of in a of of binding and the binding at The a and the were with of the with of of the with DNA or with and a and in and were with and by a with and to the Replication at Ter and the the replication termini from is in The of the Ter sites, and we this and technique by the the T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar) in the the and yeast were with the and were in and the DNA as of the that with DNA is in The of the is in form in with two tandem termination Ter1 and were the of the forks to at Ter1 and that were at In to the Ter the two were in the The are by of forks from the with the forks that were from the and and at Ter1 and work that although of Ter1 located the and to Ter2 of sequences located not only in this but also of an located of the site T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar). The region located of the is of Ter2 T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar). The mutations and specifically and the mutation located in the Ter2 but not of mutations are and of We to the of Fob1p in replication termination by to a of the K. Keil R.L. G.S. Cell. Full Text PDF PubMed Scopus Google Scholar, Keil R.L. PubMed Google Scholar). The of the is in yeast by R. Keil G.S. Keil R.L. PubMed Google Scholar, Keil R.L. PubMed Google Scholar) tandem of and a the In between the tandem sequences is a in the of the a of the We the from this by as and a or a the In the of FOB1, the between the tandem sequences in a as a and the but a replication The eliminated from the to the of the the present in the of in We the in by and the of DNA the and we that specific we also mutant that did or did not In this we mutation as L104S that In a mutation that by the in to a a mutant form that did not the the sequences are located in the of a the did not have a A. B. P. J. M. Mol. Cell. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar). The and a mutation as Keil R.L. PubMed Google Scholar) that are presented here as in this to the an of Fob1p to or were mutations that global misfolding of the mutant form of the protein. We that global misfolding or many of the of the mutant form such as to the is a nucleolar Prusty R. M. P. Keil R.L. Mol. Cell. 1999; Full Text Full Text PDF Scopus Google and S. C. P. J. PubMed Scopus Google Scholar), to and the to with We to the of the mutant of Fob1p and the as of Fob1p with and with is to with itself T. T. R. M. M. Proc. Natl. Acad. Sci. U. S. A. 2001; 98: PubMed Scopus Google Scholar) and with a protein encoded by a yeast called YDR026C that has no P. Lockshon D. M. P. A. B. D. T. M. M. S. J.M. 2000; PubMed Scopus Google Scholar). We of the and the mutant to and protein-protein First, we to interaction of the and the mutant the of work we that with itself as by the In a the between two or between the form and the protein. We also that the form in the and in replication termination We the of and YDR026C as in the to protein-protein The and the and were The of and are in from of were and In the only and L104S the and did not show and were in and in in we from that the and the L104S mutant form show the and the mutant were in this We to the interaction of and the mutant of with we the YDR026C in a that tandem of yeast Ter1 sites at the of yeast DNA with the of the to of a or a In this YDR026C as a protein that to bind to the Ter region of yeast We and P. Lockshon D. M. P. A. B. D. T. M. M. S. J.M. 2000; PubMed Scopus Google Scholar) that YDR026C with in a we have the interaction of and the mutant of with YDR026C as an of global misfolding by the mutations in In the FOB1, and interaction with the and no such interaction and were also and by The of that L104S and mutant proteins with the mutant that The YDR026C locus a protein that in a binding to K. Mohanty and D. YDR026C interaction with we to this interaction is fork arrest. We a of the YDR026C locus and to fork arrest in the The and that the and the YDR026C were of fork arrest at the Ter sites. The and that DNA interaction fork of the protein-protein with were replication termination. The Fob1p and L104S and in the of Fob1p to and in yeast that Fob1p is a nucleolar protein Prusty R. M. P. Keil R.L. Mol. Cell. 1999; Full Text Full Text PDF Scopus Google Scholar, S. C. P. J. PubMed Scopus Google Scholar). We the of the and the mutant of as another of the of the protein. We of FOB1, and with a A. A. A. P. 1998; 14: PubMed Scopus Google Scholar). with a or mutant were in and The were a and in in or in 5 the of and of the and that of are in the and the is to a of the the in The of the the with Prusty R. M. P. Keil R.L. Mol. Cell. 1999; Full Text Full Text PDF Scopus Google Scholar, S. C. P. J. PubMed Scopus Google Scholar) that Fob1p to the The that the L104S and the mutations did not the and of the mutant of the protein the The protein-protein interaction and the suggested that the L104S mutation did not cause a global misfolding of the mutant form of the protein. The L104S that the L104S mutation abolished the of to to arrest replication In to this we to B.J. Fangman W.L. Cell. Full Text PDF PubMed Scopus Google Scholar) of replication fork the region of a of the locus were with a that the or a mutant form of and the were to in and Replication were by The DNA with and in The were and with a specific to the Ter The present in the as did not a Ter the also fork arrest as by the of the Ter the of the The L104S mutant failed to promote termination of replication as by the of a Ter The protein the replication fork arrest the of fork arrest by the L104S mutation with of However, this to by a global misfolding of the mutant form of the protein as or were by the The mutant form replication fork and but interaction and is to have a protein. that although it to arrest replication The mutant the of of the and in the of Fob1p a and to and this protein from coli the and the protein it to and the protein failed to bind to Ter DNA with of to the binding of Fob1p to the Ter sites by the that Fob1p bind to the Ter sites interaction with a DNA binding protein. However, and of the protein from yeast the of a of a DNA protein. We Fob1p as a in The an site by a site that in by a B. M. B. 2001; PubMed Scopus Google Scholar) to the of The protein the of an We have that the protein as as the protein in in the and fork arrest in as by not We have also a protein with the and the the of the proteins by not The of the protein is in of the the protein were by to the of the protein. DNA binding were as to the of the protein the of of the protein and The protein of a of Fob1p in to the protein. Fob1p to the Ter Fob1p protein binds to Ter DNA by itself or in with we the purified protein DNA We developed a interaction as The is in The the Fob1p were as and the of and by to in the of The were with of binding the were at with the specific DNA that of an the two Ter sites and by DNA that with The were and the with as The were in a The of no detectable binding the to the Fob1p and In Ter DNA or Ter DNA with the the only the Ter specifically to the protein the and In this the DNA with only DNA In to a of Ter another of the also In to that the sequence-specific binding by Fob1p and not by a protein we the binding with purified Fob1p and Fob1p separately to the Ter1 and Ter2 and the binding In to the binding sequences and to the of the we of at the Ter1 and Ter2 sites that Ter1 or Ter2 T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar). The mutant that has a at the Ter1 site is to Ter1 but not Ter2 and the mutation at the Ter2 but not Ter1 T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar). We to a DNA that a Ter1 site specifically to Fob1p and the mutations abolished the DNA binding of are in in the the Ter1 the it to Fob1p protein In the the mutation the Ter1 with only the the is no binding of the DNA to the Fob1p protein a DNA the the no binding to the Fob1p protein We have the binding with purified protein with The Ter2 site a an and an as mutations in the are to Ter2 T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar). The mutation and is to replication termination at Ter2 T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar). and Keil G.S. Keil R.L. PubMed Google Scholar) have that the mutations and also the We also to binding of Fob1p to the site and the the or the mutation were and to Fob1p the the it to the as in B. However, the DNA the mutation the binding reduced We also with mutations in the and this DNA the Fob1p the binding abolished we a of that the and binding to The DNA the Fob1p and show that Fob1p protein did not bind to the to Fob1p at the and the in Ter2 DNA binding to Fob1p protein. of Ter2 showing the The were and of showing of Fob1p binding to and sequences. the binds to the has in Fob1p The mutant and the not show The L104S of the of Fob1p to Ter the L104S mutant of Fob1p is in replication fork we to it is as a in DNA We L104S and the proteins as of and L104S were and were as and as in of of the and the mutant form to the were to that of proteins were present in and that were DNA with of proteins the in the of and with Fob1p to the the mutant L104S a in binding to the Ter1 we that the L104S mutation abolished replication termination in by the interaction of the mutant form of the protein with Ter1 The of action of Fob1p protein of S. cerevisiae is of not only of in replication termination but also in Prusty R. M. P. Keil R.L. Mol. Cell. 1999; Full Text Full Text PDF Scopus Google Scholar). In this we show the that Fob1p is a protein and that this binding is replication fork arrest at the two Ter sites present in of the rDNA lines of evidence the First, a mutation L104S did not cause misfolding of the protein as by of many of the of the mutant form of the protein but abolished fork arrest and specific binding to the Ter2 sequences. Second, mutations in the sequences of Ter1 and Ter2 that separately the of Fob1p to replication at the two sites abolished binding of the protein to the sites. The that purified Fob1p specifically binds to the two Ter sites with the of evidence that Ter DNA-Fob1p interaction is a step in replication termination at the Ter sites. that Ter1 a of sequences that binds specifically to Ter2 of two called and of only binds to However, mutations in and fork arrest T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar). is that a site Fob1p binding that binding of the protein to of this is in in the region of Ter2 not to fork arrest but a in the of fork arrest T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar). to the of fork arrest from a of the of replication termination in We have that the interaction of Tus protein with the Ter sites of coli and interaction between helicase and the Tus protein are to cause fork arrest (5.Mulugu S. Potnis A. Shamsuzzaman Taylor J. Alexander K. Bastia D. Proc. Natl. Acad. Sci. U. S. A. 2001; 98: 9569-9574Crossref PubMed Scopus (55) Google Scholar). this in we present a of fork arrest in The that to the Ter sites, the helicase of this the of the helicase that the fork in the region of rDNA is not although the of yeast to the helicase A. Mol. Cell. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, C. M. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, K. J.A. 2000; PubMed Scopus Google Scholar, K. Mol. Biol. Cell. 2001; PubMed Scopus Google Scholar). The have been in and in coli and have been purified A. Mol. Cell. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, C. M. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). work that a of S. cerevisiae has helicase M. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). have been a of S. pombe J. Proc. Natl. Acad. Sci. U. S. A. 2001; 98: PubMed Scopus Google Scholar). In to the two the and fork movement replication termination in the rDNA region Cell. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar). to the of of Fob1p as in this work in to the of the terminator protein. Fob1p arrest fork by binding to Ter In a binding fork but it to fork arrest. In the it to Fob1p the proteins the to the the Ter1 and Ter2 sequences bind to the two sequences have no detectable the as to Fob1p has a DNA binding that sequences or are two of the Ter sequences. binding that Fob1p has a DNA binding or a that with Ter1 and K. Mohanty and D. in with are in to the to between Fob1p and the Ter that the of the DNA binding of protein-protein Fob1p have been to of to in fork arrest. First, Fob1p with itself and is an protein. However, is not to replication as by the mutant form that is of fork arrest but has the to as in a Second, Fob1p as in this work and by P. Lockshon D. M. P. A. B. D. T. M. M. S. J.M. 2000; PubMed Scopus Google Scholar), with a protein. the presented here that the interaction is not in fork arrest. and have suggested that Fob1p has to the of M. Sci. PubMed Scopus Google Scholar). In this it is to that a 7.Ward T.R. Hoang M.L. Prusty R. Lau C.K. Keil R.L. Fangman W.L. Brewer B.J. Mol. Cell. Biol. 2000; 13: 4948-4957Crossref Scopus (52) Google Scholar) with Ter sites the rDNA in the of a Fob1p and in the of a A. Hernandez P. Krimer D.B. Schvartzman J.B. Nucleic Acids Res. PubMed Scopus Google Scholar), a J. A. J. R. Proc. Natl. Acad. Sci. U. S. A. 2000; PubMed Scopus Google Scholar, J. J. R. Cell. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, J. R. J.M. Proc. Natl. Acad. Sci. U. S. A. 2000; PubMed Scopus Google Scholar, S. M. Cold Spring Harbor Biol. 2000; PubMed Scopus Google Scholar). In the of such not A. Hernandez P. Krimer D.B. Schvartzman J.B. Nucleic Acids Res. PubMed Scopus Google Scholar). We have a of mutations of at the region to the We to the and to the is fork arrest. that work a novel technique the of sequence-specific interaction a and a technique is and has to and In Fob1p and the that it specifically with the Ter1 and Ter2 sequences evidence with to the of replication termination.