It has been observed that when pBR322 and pUC19 plasmids (derivatives of pColE1) are co-transformed the pBR322 plasmid is selectively excluded from the cell. There are several potential factors that may explain this observation. One particular factor may be that pBR322 encodes the gene for the Rop protein, not seen in pUC19. This protein is involved in stabilizing the interaction between RNA I ...

The two commonly used plasmid vectors, pBR322 and pUC19, are both derivatives of the parent plasmid, pColE-1. However, it has been observed that pBR322 is excluded from the host cells following co-transformation of pBR322 and pUC19. One potential explanation for this exclusion effect is the presence of a functional rop gene in pBR322. The rop gene encodes for a protein that stabilizes the inter...

When pBR322 is manually microinjected into the nuclei of quiescent Swiss 3T3 cells it stimulates the incorporation of [3H]thymidine into DNA. The evidence clearly shows that this increased incorporation that is detected by in situ autoradiography in microinjected cells represents cellular DNA synthesis and not DNA repair or plasmid replication. The effect is due to pBR322 and not due to impurit...

In vivo recombinational cloning in yeast is a very efficient method. Until now, this method has been limited to experiments with yeast vectors because most animal, insect, and bacterial vectors lack yeast replication origins. We developed a new system to apply yeast-based in vivo cloning to vectors lacking yeast replication origins. Many cloning vectors are derived from the plasmid pBR322 and h...

pBR322 plasmid DNA was treated with methylene blue plus visible light (MB-light) and tested for transformation efficiency in Escherichia coli mutants defective in either formamidopyrimidine-DNA glycosylase (Fpg protein) and/or UvrABC endonuclease. The survival of pBR322 DNA treated with MB-light was not significantly reduced when transformed into either fpg-1 or uvrA single mutants compared wit...

This experiment attempted to study the replication control of pBR322 during stringent growth in E. coli. If the stringent response is responsible for the control of pBR322 copy number, an amino acid-starved stringent E. coli strain would be expected to decrease plasmid replication, whereas relaxed mutant strains would exhibit amplification of pBR322. In this experiment, the growth rate of an E....

Plasmid pBR322 derives from plasmid ColE1 and does not replicate in Escherichia coli strains lacking DNA polymerase I. Hybrids between pBR322 and a plasmid isolated from Staphylococcus aureus, pC194, replicate in such E. coli strains, provided that the pC194 replication region is intact. Inactivation of the pBR322 replication region does not interfere with the replication of hybrids in E. coli....

We analyzed the functionality of different dnaA protein binding sites by assaying in vitro dnaA-dependent replication of pBR322 derivatives. Single dnaA sites from oriC and from the mioC and dnaA gene promoters were active when combined with the primer generating element of pBR322 in a proper distance. Prereplisome assembly did not require sequences in addition to the 9-base pair consensus dnaA...

SV40 DNA form I is expressed efficiently after its injection into the nuclei of Xenopus laevis oocytes, resulting in the synthesis of RNA and protein products of both viral late and early transcription units. However it was observed that injection of SV40 genes cloned into pBR322 or related plasmids yielded vastly reduced quantities of viral DNA and proteins. If SV40 DNA was cleaved from the pl...