I've got trouble in cloning.
I use the Forward primer of Insert (PCR) and reverse primer of pUC19 to amplify PCR region, becauz RE cut forward primer of pUC19. After ligation, gel agarose electrophoresis is ok, I see the size band I wanted, but when I tranform vector-insert into E.coli DH5alfa, then extract vector-PCR (vector-insert purified), and also PCR with Fw primer of insert and reverse primer oF pUC19, but beside the wanted band, it appear 500bp band.
Before I extract vector-insert, cell lysed and PCR, and 500bp band are appeared.
I dont know why. I think it dont cause plasmid extraction