Low rate of replication fork progression lengthens the replication timing of a locus containing an early firing origin.
Invariance of temporal order of genome replication in eukaryotic cells and its correlation with gene activity has been well-documented. However, recent data suggest a relax control of replication timing. To evaluate replication schedule accuracy, we detailed the replicational organization of the developmentally regulated php locus that we previously found to be lately replicated, even though php gene is highly transcribed in naturally synchronous plasmodia of Physarum. Unexpectedly, bi-dimensional agarose gel electrophoreses of DNA samples prepared at specific time points of S phase showed that replication of the locus actually begins at the onset of S phase but it proceeds through the first half of S phase, so that complete replication of php-containing DNA fragments occurs in late S phase. Origin mapping located replication initiation upstream php coding region. This proximity and rapid fork progression through the coding region result in an early replication of php gene. We demonstrated that afterwards an unusually low fork rate and unidirectional fork pausing prolong complete replication of php locus, and we excluded random replication timing. Importantly, we evidenced that the origin linked to php gene in plasmodium is not fired in amoebae when php expression dramatically reduced, further illustrating replication-transcription coupling in Physarum.
Bénard
Marianne
M
CNRS-FRE 2937, Institut André Lwoff, BP8, 94800 Villejuif, France. benard@vjf.cnrs.fr
Maric
Chrystelle
C
Pierron
Gérard
G
D000818:Animals; D004261:DNA Replication / Q000187:drug effects; D042522:DNA Replication Timing; D005786:Gene Expression Regulation; D017125:Genes, Protozoan; D006918:Hydroxyurea / Q000494:pharmacology; D016839:Physarum polycephalum / Q000235:genetics* / Q000254:growth & development; D011401:Promoter Regions, Genetic; D018741:Replication Origin; D016196:S Phase / Q000235:genetics; D014158:Transcription, Genetic
D006918:Hydroxyurea
Mol Cell Biol. 1992 Oct;12(10):4305-13
1406623
Mol Cell Biol. 1993 Jan;13(1):449-61
8093328
Nucleic Acids Res. 1999 May 15;27(10):2091-8
10219081
Methods Enzymol. 1995;262:613-27
8594382
Proc Natl Acad Sci U S A. 1965 May;53(5):924-31
5222560
J Cell Biol. 1998 Mar 23;140(6):1285-95
9508763
Proc Natl Acad Sci U S A. 1973 Dec;70(12):3395-9
4128545
Cell. 1988 Nov 18;55(4):637-43
3052854
Science. 2001 Oct 5;294(5540):115-21
11588253
Nucleic Acids Res. 1992 Jul 11;20(13):3309-15
1630902
Mol Cell. 2001 May;7(5):971-80
11389844
Proc Natl Acad Sci U S A. 1984 Apr;81(7):1991-5
6326095
Trends Genet. 2005 Aug;21(8):444-9
15951049
Cell. 1987 Nov 6;51(3):463-71
2822257
Hum Mol Genet. 2004 Jan 15;13(2):191-202
14645202
Nat Rev Genet. 2001 Aug;2(8):640-5
11483989
Proc Natl Acad Sci U S A. 2005 May 3;102(18):6419-24
15845769
Bioessays. 2003 Feb;25(2):116-25
12539237
Exp Cell Res. 1990 Feb;186(2):299-305
1967581
Mol Cell. 2003 Dec;12(6):1525-36
14690605
Biochim Biophys Acta. 1966 Jan 18;114(1):108-15
5936951
Cell. 1978 Dec;15(4):1519-26
729005
Biochim Biophys Acta. 1969 Jan 21;174(1):246-52
4237205
Exp Cell Res. 1992 Aug;201(2):506-13
1353456
Trends Cell Biol. 1993 May;3(5):161-7
14731611
Nat Cell Biol. 2006 Dec;8(12):1313-6
17139278
Methods Mol Biol. 2004;277:19-28
15201446
Nat Genet. 2002 Nov;32(3):438-42
12355067
EMBO Rep. 2006 Aug;7(8):812-6
16845368
Nucleic Acids Res. 1998 May 1;26(9):2042-49
9547257
Curr Opin Cell Biol. 2002 Jun;14(3):377-83
12067662
Genes Dev. 2004 Dec 15;18(24):3094-105
15601823
EMBO Rep. 2003 May;4(5):474-8
12776736
Science. 1995 Nov 10;270(5238):994-7
7481806
Nucleic Acids Res. 1989 Jan 25;17(2):553-66
2915922
Genes Dev. 2002 Jun 1;16(11):1383-96
12050116
J Cell Sci. 1980 Feb;41:105-13
7364877
Genes Dev. 2004 Feb 15;18(4):397-410
14977920
Eur J Cell Biol. 1982 Nov;29(1):104-13
6217973
Mol Cell Biol. 1996 Mar;16(3):968-76
8622700
Mol Biol Cell. 2006 Jan;17(1):308-16
16251353
Am J Hum Genet. 1987 Feb;40(2):151-73
3551593
Mol Biol Cell. 1992 Sep;3(9):999-1013
1330093
Nat Cell Biol. 2006 Feb;8(2):148-55
16429127
Nat Rev Mol Cell Biol. 2003 Jan;4(1):25-32
12511866
Proc Natl Acad Sci U S A. 2004 Dec 21;101(51):17771-6
15591350
Nucleic Acids Res. 1995 May 11;23(9):1447-53
7784195
Nucleic Acids Res. 2002 Jun 1;30(11):2261-9
12034812
Mol Biol Cell. 2006 Dec;17(12):5337-45
17005913
Mol Cell. 2005 Nov 23;20(4):575-87
16307921
Biochemistry. 1979 Nov 27;18(24):5294-9
518835