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Wednesday, November 21, 2007

M.sc Biotech PhiX174

PhiX174 description & restriction Map
PiX174 was the first DNA virus discovered to have a single-stranded, circular genome. PhiX174 DNA is 5386 nt in length. The DNA strand packaged into the virion is termed the “plus” strand. After entering the cell, PhiX174 DNA is used as a template for minus-strand synthesis, producing double-stranded DNA. The conversion of plus DNA strands to double-strands does not require any of the phage genes to function. The double-stranded DNA can then be transcribed, resulting in synthesis of phage-encoded proteins. Synthesis of single-stranded (plus) DNA requires the phage-encoded gene A protein. DNA synthesis is initiated at ori (+) and proceeds in the direction indicated. Late in infection, the single-stranded circles are encapsidated into new virions. The cycle terminates by cellular lysis, mediated by phage gene E encoded protein.
The genes identified in phage PhiX174 are shown on the map. All genes are transcribed clockwise. Enumeration of phage DNA begins with the unique PstI site and continues clockwise around the viral (+) strand in the 5'=>3' direction. The map shows enzymes that cut PhiX174 DNA once. Enzymes produced by Fermentas are shown in blue. The coordinates refer to the position of the first nucleotide in each recognition sequence.
References
Air, G.M., Coulson, A.R., Fiddes, J.C., Friedmann, T., Hutchison, C.A., Sanger, F., Slocombe, P.M. and Smith, A.J., Nucleotide sequence of the F protein coding region of bacteriophage PhiX174 and the amino acid sequence of its product, J. Mol. Biol., 125, 247-254, 1978.
Sanger, F., Air, G.M., Barrell, B.G., Brown, N.L., Coulson, A.R., Fiddes, C.A., Hutchison, C.A., Slocombe, P.M. and Smith, M., Nucleotide sequence of bacteriophage PhiX174 DNA, Nature, 265, 687-695, 1977.
Sanger, F., Coulson, A.R., Friedmann, T., Air, G.M., Barrell, B.G., Brown, N.L., Fiddes, J.C., Hutchison, C.A. III., Slocombe, P.M. and Smith, M, The nucleotide sequence of bacteriophage PhiX174, J. Mol. Biol., 125, 225-246, 1978.
Enzymes which cut PhiX174 DNA once:
AasI 5171, AatII 2782, AdeI 5183, Alw44I 4779, BaeI 2581, BcnI 2800, BoxI 1694, BseSI 4779, Bsh1285I 4601, BtsI 2203, Cfr42I 2859, Eam1105I 1760, Eco47I 5042, Eco88I 162, Eco147I 4486, FalI 3172, MbiI 530, MunI 3939, NsbI 155, OliI 2912, PauI 5348, PsiI 2304, PstI 5382, SapI 3745, SexAI 3499, SspI 1007, XhoI 162.

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