Nucleotide sequence and transcription of the left early region of Streptococcus pneumoniae bacteriophage Cp-1 coding for the terminal protein and the DNA polymerase.
Cp-1 is a small virulent bacteriophage infecting Streptococcus pneumoniae. It has a linear, double-stranded genome of about 19 kb that replicates by a protein-priming mechanism. We have determined the nucleotide sequence of the leftmost 4780 bp of the DNA of this bacteriophage; computer analysis revealed that this fragment contains seven open reading frames (ORFs) which could encode polypeptides containing more than 50 amino acids. The ORFs are clustered in two groups separated by noncoding intergenic regions. Two of these ORFs code for the terminal protein and a specific DNA polymerase that participate in the replication of the DNA. The predicted amino acid sequence of the terminal protein shows significant similarity with the terminal protein of Bacillus subtilis phage phi 29, and Cp-1 DNA polymerase is homologous to the subgroup of eukaryotic-type DNA polymerases that use a protein as a primer. Combined Northern blots and primer extension experiments have allowed us to map the 5' initiation sites of left early transcripts. These studies revealed that transcripts elongate from left to right and identified the left early promoters.
Martín
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AC
Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
López
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R
García
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P
D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D015152:Blotting, Northern; D017124:Conserved Sequence; D017931:DNA Primers; D004261:DNA Replication; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000096:biosynthesis* / Q000235:genetics; D016679:Genome, Viral; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D013296:Streptococcus pneumoniae / Q000821:virology*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000096:biosynthesis* / Q000235:genetics; D014779:Virus Replication
D017931:DNA Primers; D004279:DNA, Viral; D012333:RNA, Messenger; D014764:Viral Proteins; D004259:DNA-Directed DNA Polymerase