Evidence for inclusion of a segment of Escherichia coli genomic DNA in bovine tooth germ mRNA encoding salivary proline-rich protein P-B

Abstract

In the course of cloning of bovine cDNA for proline-rich protein (PRP) P-B from bovine tooth germ cDNA, we found that one clone with 662 bp contained a 5'-terminal 393 bp (1-393 bp) sequence essentially identical to that of human P-B cDNA (154-546 in D29833) and bovine P-B cDNA (1-356 bp in AB192573) and a sequence of 233 bp (394-626 bp) highly homologous to the segment of E. coli K12 genomic DNA (365511-365744 in NC000913). Although the latter sequence is contained in the vector pT7Blue, which we used, our results show that this chimeric structure in bovine tooth germ P-B cDNA is not an artifact formed during the cloning process, but intrinsic to the bovine genome since the chimeric structure was detected in bovine tooth germ and bovine genomic DNA.

Unusual amplification in polymerase chain reaction for a plasmid containing an insert derived from bovine genomic DNA

“…The black bar indicates B6; (d) A proposed mechanism for generation of b6-110 depending on the palindrome structure in B6. B6 contains the sequence derived from bovine genomic DNA ( Such an unusual amplification generated under certain conditions in a DNA sequence may be one of the mechanisms for the genetic recombination found in our previous study [8]. Study to examine possible occurrence of E. coli DNA-derived nucleotide sequences in bovine genomic DNA is now in progress.…”

“…Nucleotide sequences were analyzed by the dye terminator method on an ABI PRISM 310NT Genetic Analyzer (Applied Biosystems Japan Ltd., Tokyo, Japan) as described previously [5,8].…”

“…Following the finding of Strawich and Glimcher that a homologous protein is present in bovine tooth germ [6], we started a study on bovine P-B [7]. In the course of cloning bovine cDNA for P-B, we found a segment of E. coli genomic DNA in bovine tooth germ mRNA encoding P-B [8]. Consequently, we examined the possible occurrence of E. coli DNA-derived nucleotide sequences in bovine genomic DNA using a plasmid library constructed from EcoRV digests of the bovine DNA.…”