Gene dusters

Genetic analysis has shown that there is only one promoter and no internal termination large operon sequences have been found, indicating that this gene duster is one very large operon. 

There is a second large gene duster, about 35kb, also involved in the synthesis of xanthan. The predse function is unknown but it is thought to encode for proteins involved in the synthesis of sugar nucleotide diphosphates. 

Summers, R.G., E. Wendt-Pienkowsky, H. Motamedi, C.R. Hutchinson, CR. 1993. The tcmVI region of the tetracenomycin C biosynthetic gene duster of Streptomyces glaucescens encodes the tetracenomycin FI monooxygenase, tetracenomycin F2 cyclase, and most likely, a second cyclase. J. Bacteriol. 175 7571-7580. 

A 26-kb gene duster encoding enzymes for synthesis of the blue antibiotic actinorhodin by Streptomyces coelicolor has been cloned and sequenced The three large 10-kb genes required for formation of the broad-spectrum antibiotic erythromycin by Saccharopolyspora erythraea have also been cloned and sequenced. In both cases, the genes... 

Figure 10.1 Architecture of Axpergillus secondary metabolite gene clusters. Shown arc the A. nidulans Sterigmatocystin (ST) (A) and Penicillin (PN) (B) gene dusters as well as the A. terreus Lov gene cluser (C). The rectangle indicates the portion of the Lov cluster that has been heterologously expressed in A. nidulans, as discussed in the text.

Bam HI restriction map giving approximate size (Kb) of the tcagmenls in the 16 Kb xanihan gene duster... 

Murakami S, Takashima A, Takemoto J, Takenaka S, Shinke R, Aoki K (1999) Cloning and sequence analysis of two catechol-degrading gene dusters from the aniline-assimilating bacterium Frateuria species ANA-18. Gene 226 189-198... 

Vujaklija D, Ueda K, Hong S, Beppu T, Horinouchi S. Identification of an A-factor-dependent piomotor in the streptomycin biosynthetic gene duster of Streptomyces griseus. Mo Gen Genet 1991 229 119-128. 

Malpartida F, Hop wood DA. Physical and genetic characterization of the gene duster for the antibiotic actinorhodin in Streptomyces coelicolor A3(2). Mol Gen Genet 1986 205 6fr-73. 

Hostrf TJ. DeHoff BS, Rosteck PR Jr, Balt RH. Cloning and sequence sampling of the Strep-tomyces fradiae lipopeptide antibiotic biosynthetic gene duster (manuscript in preparation). 

Several gene dusters encoding the enzymes of polyketide synthesis have been cloned (partially or completely). Aromatic polyketides (e.g., tetracyclines, actinorho-dine, and anthracyclines) are synthesized by type II PKSs, which are multienzyme OMn-plexes similar to FAS type II (63). In contrast, the polyketide chain of mactolide antibiotics such as erythromycin and avermectin are synthesized by PKS type I, consisting of large multifunctional polypeptides similar to FAS type I but composed of repeated units or "modules" with each active site carrying out only one reaction in the assembly and modification of each carbon chain (64,65). 

Schweeke T, Aparicio ]F, Molnar I, Konig A, Khaw LE, Haydock SF, Oliynyk M, Caffrey P, Cortes J, Lester JB, Elohm GA, Staunton J, Leadlay PF. The biosynthesis gene duster for the polyketide immunosuppressant rapamycin. Proc Natl Acad Sci USA 1995 93 7839-7843, Decker H, Summers RG, Hutchinson CR. Overproduction of all of the components of a type II polyketide synthase or only the acyl carrier protein stimulates the production of tetra-cenomycin C biosynthetic intermediates In Streptomyees glaMcescens. J Amibioc 1994 47 54-63. 

Lee B (1996) Bacteria-based processes and products. In Lee B (ed) Fundamentals of food biotechnology. VEH, New York, pp 219—290 Lee JH, li X, O Sullh DJ (2011) Transcription analysis of a lantibiotic gene duster from Bifidobacterium longum DJOIOA. Appl Environ Microbiol... 

Sosio M, Elossi E, Bianchi A, Donadio S (2000) Multiple gene synthetase gene dusters in actinomycetes. Mol Gen Genet 264 213-221 Stachelhaus T, Schneider A, Marahiel M (1995) Rational design of peptide antibiotics by targeted replacement of bacterial and fungal domains. Sdence 269 69—71... 

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