| Autor: |
Togni, Pietro De, Fox, Henry B., Morrissey, Suzanne, Tansey, Lisa R., Levy, Stuart B., Babior, Bernard M. |
| Zdroj: |
Blood; February 1988, Vol. 71 Issue: 2 p463-466, 4p |
| Abstrakt: |
The plasmid pUC18 contains a lacZ a-complementation gene that codes for a small peptide that can complement the AM15 mutation of the Escherichia colilacZ (β-galacto-sidase) gene, converting bacteria carrying that mutated gene from the lac Z-to the lacZ+phenotype. This plasmid was used in experiments designed to study mutagenesis by human neutrophils. E colicarrying pUC18 were incubated with neutrophils under conditions in which little ingestion of the bacteria took place; the plasmid was then isolated and transformed into an E colistrain (BOZO) that carries the lacZAM15 mutation. Of these transformants, 11 of 205,000 were lac-, suggesting that in these 11, α-comple-mentation had been lost through a mutation. No lac-colonies were detected among several hundred thousand BOZO transformed with plasmid isolated from incubations in which phagocytosis could take place, nor from incubations from which neutrophils were omitted. Despite the lac-phenotype of these 11 transformants, plasmids reiso-lated from nine of them showed normal a-complementing ability when transformed into fresh BOZO. These findings indicated that in these nine, the mutations were located in the chromosomes of the transformed BOZO. It thus appears that on exposure to activated neutrophils, a plasmid may acquire a lesion (?mutation) that can somehow be transferred to the genome of a recipient microorganism, resulting in repair of the damaged plasmid accompanied by mutation of the recipient's chromosome. Restriction mapping of the DNA from four of these nine chromosomal mutants suggested that the mutations did not represent major insertions or deletions in the portion of the bacterial chromosome corresponding to the pUC18 lac operon insert, nor in the remainder of the lacZΔM1 5 gene. These results confirm previous work showing that exposure to activated neutrophils can induce mutations in biological systems, and provides an experimental model in which the mechanism of neutrophil-mediated mutagenesis may be examined.1988 by Grune & Stratton, Inc. 0006-4971/88/7102-0028$3.00/0 |
| Databáze: |
Supplemental Index |
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