question about vectors?

Question

Are pUC 18 and pUC 8 the same thing? If not, whats the difference?

Answer 1

They are essentially the same thing, in that they both confer ampicillin resistance and have beta galactosidase for blue-white selection of clones carrying inserts. However, pUC 18 appears to have many more restriction sites in the polylinker. See maps below for a closer view of the polylinker.

Answer 2

Expression vector; cloning vector with multiple restriction enzyme linker; derived from pBR322 and M13mp8 - vector; pUC8 allows direct selection of cloned DNA because of alpha complementation; allows using the same primer as for the M13 system; pUC8 allows to clone double-digested restriction fragments separately in both orientation with respect to the lac promoter; replicon: pMB1; not self-transmissible.
Distributed in Escherichia coli K12 JM83

pUC18 plasmids contain: (1) the pMB1 replicon rep responsible for the replication of plasmid (source - plasmid pBR322). The high copy number of pUC plasmids is a result of the lack of the rop gene and a single point mutation in rep of pMB1; (2) bla gene, coding for beta-lactamase that confers resistance to ampicillin (source - plasmid pBR322). It differs from that of pBR322 by two point mutations; (3) region of E.coli operon lac containing CAP protein binding site, promoter Plac, lac repressor binding site and 5'-terminal part of the lacZ gene encoding the N-terminal fragment of beta-galactosidase (source - M13mp18/19). This fragment, whose synthesis can be induced by IPTG, is capable of intra-allelic (alfa) complementation with a defective form of beta-galactosidase encoded by host (mutation lacZDM15). In the presence of IPTG, bacteria synthesise both fragments of the enzyme and form blue colonies on media with X-Gal. Insertion of DNA into the MCS located within the lacZ gene (codons 6-7 of lacZ are replaced by MCS) inactivates the N-terminal fragment of beta-galactosidase and abolishes alfa-complementation. Bacteria carrying recombinant plasmids therefore give rise to white colonies.