Complete sequence of plasmid pmp1 from the marine environmental vibrio vulnificus and location of its replication origin

TY - JOUR

T1 - Complete sequence of plasmid pmp1 from the marine environmental vibrio vulnificus and location of its replication origin

AU - Ruifu, Zhang

AU - Ji-Dong, Gu

N1 - Funding Information: This research was financially supported by 863 Project (no. 2002AA601160) supplement fund of The University of Hong Kong and RGC Central Allocation CA00/01.SC01. We would also like to thank the laboratory assistance of Miss Jessie Lai.

PY - 2009/7

Y1 - 2009/7

N2 - A novel cryptic plasmid, pMP1, from an environmental Vibrio vulnificus MP-4 isolated from Mai Po Nature Reserve in Hong Kong, has been characterized. The 7.6-kb plasmid had guanine-cytosine content of 40.03% and encoded four open reading frames (ORFs) with >100 amino acids. The predicted protein of ORF1 contained 478 amino acids showing 29% identity and 50% similarity over 309 amino acids to the integrase of Vibrio cholerae phage VP2. ORF2 encoded a putative protein of 596 amino acids, which were 23% identity and 42% similarity over 455 amino acids to the tail tape measure protein TP901 of Chromohalobacter salexigens phage. ORF3 and ORF4 encoded putative proteins of 103 and 287 amino acids, respectively, but showed no homologies to any known proteins. Further experiments indicated that a 3.2-kb fragment from EcoRI digestion could self-replicate. Analysis indicated that a sequence upstream of ORF4 had the features characteristic of theta-type replicons: AT-rich region, six potential direct repeats (iterons) spaced approximately two DNA helical turn apart (about 23 bp), two copies of 9 bp dnaA boxes, three Dam methylation sites, and five inverted repeats. Complementation experiments confirmed that the protein encoded by ORF4 was required for plasmid replication. We propose that ORF4 encode a new type of Rep protein and pMP1 is a new type of theta plasmid.

AB - A novel cryptic plasmid, pMP1, from an environmental Vibrio vulnificus MP-4 isolated from Mai Po Nature Reserve in Hong Kong, has been characterized. The 7.6-kb plasmid had guanine-cytosine content of 40.03% and encoded four open reading frames (ORFs) with >100 amino acids. The predicted protein of ORF1 contained 478 amino acids showing 29% identity and 50% similarity over 309 amino acids to the integrase of Vibrio cholerae phage VP2. ORF2 encoded a putative protein of 596 amino acids, which were 23% identity and 42% similarity over 455 amino acids to the tail tape measure protein TP901 of Chromohalobacter salexigens phage. ORF3 and ORF4 encoded putative proteins of 103 and 287 amino acids, respectively, but showed no homologies to any known proteins. Further experiments indicated that a 3.2-kb fragment from EcoRI digestion could self-replicate. Analysis indicated that a sequence upstream of ORF4 had the features characteristic of theta-type replicons: AT-rich region, six potential direct repeats (iterons) spaced approximately two DNA helical turn apart (about 23 bp), two copies of 9 bp dnaA boxes, three Dam methylation sites, and five inverted repeats. Complementation experiments confirmed that the protein encoded by ORF4 was required for plasmid replication. We propose that ORF4 encode a new type of Rep protein and pMP1 is a new type of theta plasmid.

KW - Cryptic plasmid

KW - Theta replication

KW - Vibrio vulnificus

KW - pMP1

UR - http://www.scopus.com/inward/record.url?scp=67349113968&partnerID=8YFLogxK

U2 - 10.1007/s10126-008-9160-3

DO - 10.1007/s10126-008-9160-3

M3 - 文章

C2 - 19009320

AN - SCOPUS:67349113968

SN - 1436-2228

VL - 11

SP - 456

EP - 462

JO - Marine Biotechnology

JF - Marine Biotechnology

IS - 4

ER -