RT Journal Article SR Electronic(1) A1 Lomovskaya, Natalie A1 Fonstein, Leonid A1 Ruan, Xiaoan A1 Stassi, Diane A1 Katz, Leonard A1 Hutchinson, C. RichardYR 1997 T1 Gene disruption and replacement in the rapamycin-producing Streptomyces hygroscopicus strain ATCC 29253 JF Microbiology, VO 143 IS 3 SP 875 OP 883 DO https://doi.org/10.1099/00221287-143-3-875 PB Microbiology Society, SN 1465-2080, AB A system for gene disruption and replacement based on a streptomycete temperate phage vector was developed to introduce DNA in the rapamycin-producing Streptomyces hygroscopicus strain ATCC 29253. This will be useful in attempts to produce, through genetic manipulation, novel forms of the therapeutically important immunosuppressive drug rapamycin. Recombinant phages were constructed from the ?31 phage derivative KC515 (c + attP) carrying a thiostrepton or viomycin resistance gene along with segments of the S. hygroscopicus chromosome. Each of the cloned segments also contained the aphll neomycin/kanamycin resistance gene to enable gene replacement by loss of the phage-derived DNA. Specific deletion of the entire polyketide synthase (PKS) believed to govern rapamycin biosynthesis resulted in the loss of rapamycin production. In contrast, disruption or deletion of a region predicted to encode four PKS open reading frames, or another region predicted to encode another PKS plus a cytochrome P450 hydroxylase and ferredoxin, had no effect on the production of rapamycin or nigericin, a polyether antibiotic also produced by S. hygroscopicus. Therefore, S. hygroscopicus may have the capacity to produce polyketides additional to rapamycin and nigericin., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-143-3-875