Avtor/Urednik | Starčič-Erjavec, Marjanca; Gaasra, Wim; van Putten, Jos; Žgur-Bertok, Darja | |
Naslov | Naravni plazmid pRK100 bakterije Escherichia coli je sestavljen kot mozaik | |
Tip | članek | |
Vir | In: Klanjšek M, editor. Raziskovalno delo podiplomskih študentov v Sloveniji. Ljubljana: Društvo mladih raziskovalcev, | |
Leto izdaje | 2003 | |
Obseg | str. 395-404 | |
Jezik | slo | |
Abstrakt | Mosaicism of the Large Natural Escherichia coli Plasmid pRK100 - In search for the evolutionary origin of the conjugative plasmid pRK100, we determined the plasmid's functional replication regions and performed targeted genetic analysis of the plasmid. Construction of minireplicons via ligation of Tn1725 with plasmid fragments and targeted cloning of putative replication regions, followed by sequence analysis indicated two functional replication regions, a plasmid F-like RepFIB and a plasmid R1-like RepFIIA replication region. Partial nucleotide sequencing of regions of the plasmid revealed genes that encode a putative enterochelin iron uptake system previously associated with an Escherichia coli pathogenicity island, PAI III536, and the pColV-like aerobactin genes. In addition, a homologue of the plasmid R100-like rmoA gene was found. PCR and hybridisation experiments further demonstrated that pRK100 harbours IS2 and IS3 insertion sequences that may have facilitated in the acquisition of elements from other DNA molecules. These data together with the previous identification of a F-like tra region and a pColIa-like colicin Ia, indicate that pRK100 has a highly mosaic structure with elements derived from many different known large natural plasmids, and also from chromosome. | |
Izvleček | Da bi osvetlili nastanek in razvoj plazmida pRK100 bakterije Escherichia coli (E. coli), smo poiskali replikacijske regije in tudi druga zaporedja, ki nakazujejo izvor plazmida. Replikacijskim regijam, ki smo jih dobili s pripravo minireplikonov s pomočjo Tn1725 ali z uporabo PCR, smo določili nukleotidno zaporedje. S primerjavo dobljenih nukleotidnih zaporedij z že znanimi zaporedji drugih replikacijskih regij, smo ugotovili, da ima plazmid pRK100 zapisa za dve replikacijski regiji: eno, podobno replikacijski regiji RepFIB plazmida F in drugo, podobno replikacijski regiji RepFIIA plazmida R1. Nukleotidna zaporedja smo določili tudi nekaterim drugim odsekom plazmida pRK100. S primerjavo le-teh zaporedij smo ugotovili, da ima pRK100 tudi zapisa za dva sistema privzema železa, enega, ki je zelo podoben enterohelinskemu sistemu, zapisanemu na kromosomskem otoku patogenosti PAI III536 uropatogenega seva bakterije E. coli, in drugega, ki je zelo podoben aerobaktinskmu sistemu plazmida pCo1V-K30. Na plazmidu pRK100 smo našli tudi zaporedje podobno gems rmoA plazmida R100. S PCR in hibridizacijo smo dokazali, da ima pRK100 tudi zapise za IS2 in IS3, ki omogočajo vključevanje genetskih elementov drugih molekul DNA. Dobljeni rezultati, z že prej znanimi zapisi podobnimi kolicinu Ia plazmida pColIa in regiji tra, podobni plazmidu F, nakazujejo, da je plazmid pRK100 sestavljen kot mozaik iz delov pridobljenih iz različnih drugih plazmidov in tudi kromosoma. | |
Deskriptorji | PLASMIDS ESCHERICHIA COLI F FACTOR REPLICON IRON BASE SEQUENCE POLYMERASE CHAIN REACTION |