Abstract: A method of generating a double stranded (ds) recombinant nucleic acid molecule covalently linked in both strands by contacting two or more ds nucleotide sequences with a topoisomerase under conditions such that both termini of at least one end of a first ds nucleotide sequence are covalently linked by the topoisomerase to both termini of at least one end of a second ds nucleotide sequence is provided. Also provided is a method for generating a ds recombinant nucleic acid molecule covalently linked in one strand, by contacting two or more ds nucleotide sequences with a type IA topoisomerase under conditions such that one strand, but not both strands, of one or both ends of a first ds nucleotide sequence are covalently linked by the topoisomerase. Compositions for performing such methods, and compositions generated from such methods also are provided, as are kits containing components useful for conveniently practicing the methods.

Abstract: A method of generating a double stranded (ds) recombinant nucleic acid molecule covalently linked in both strands by contacting two or more ds nucleotide sequences with a topoisomerase under conditions such that both termini of at least one end of a first ds nucleotide sequence are covalently linked by the topoisomerase to both termini of at least one end of a second ds nucleotide sequence is provided. Also provided is a method for generating a ds recombinant nucleic acid molecule covalently linked in one strand, by contacting two or more ds nucleotide sequences with a type IA topoisomerase under conditions such that one strand, but not both strands, of one or both ends of a first ds nucleotide sequence are covalently linked by the topoisomerase. Compositions for performing such methods, and compositions generated from such methods also are provided, as are kits containing components useful for conveniently practicing the methods.

Abstract: The isolation and characterization of genes involved in proteolytic processing in species of the genus Pichia is described. The availability of such genes has enabled the generation of strains of Pichia which are deficient in proteolytic activity, which strains are useful as hosts for the expression of proteolytically sensitive recombinant products. The isolation and characterization of additional genes from species of the genus Pichia is also described, as well as uses therefore.

Abstract: The isolation and characterization of genes involved in proteolytic processing in species of the genus Pichia is described. The availability of such genes has enabled the generation of strains of Pichia which are deficient in proteolytic activity, which strains are useful as hosts for the expression of proteolytically sensitive recombinant products. The isolation and characterization of additional genes from species of the genus Pichia is also described, as well as uses therefore.

Abstract: The isolation and characterization of genes involved in proteolytic processing in species of the genus Pichia is described. The availability of such genes has enabled the generation of strains of Pichia which are deficient in proteolytic activity, which strains are useful as hosts for the expression of proteolytically sensitive recombinant products. The isolation and characterization of additional genes from species of the genus Pichia is also described, as well as uses therefore.

Abstract: Insulin-like growth factor-1 (IGF-1), a naturally occurring, relatively short, single chain polypeptide, is prepared by growing methylotrophic yeast transformants containing in their genome at least one copy of DNA encoding IGF-1, in operational linkage with DNA encoding a signal sequence, which is effective for directing secretion of proteins from the host cells and which also includes the proteolytic processing site lys-arg and may include one or more glu-ala sequences. In preferred embodiments the signal sequence is the S. cerevisiae alpha mating factor pre-pro sequence. Expression of both the DNA encoding IGF-1 and the pre-pro signal sequence is regulated by a promoter region derived from a methanol responsive gene of a methylotrophic yeast. DNA constructs and recombinant methylotrophic yeast strains used for the expression and secretion of IGF-1 are also provided. For preferred embodiments, protease deficient Pichia pastoris strains are provided.

Abstract: The isolation and characterization of genes involved in proteolytic processing in species of the genus Pichia is described. The availability of such genes has enabled the generation of strains of Pichia which are deficient in proteolytic activity, which strains are useful as hosts for the expression of proteolytically sensitive recombinant products. The isolation and characterization of additional genes from species of the genus Pichia is also described, as well as uses therefore.

Abstract: The isolation and characterization of genes involved in proteolytic processing in species of the genus Pichia is described. The availability of such genes has enabled the generation of strains of Pichia which are deficient in proteolytic activity, which strains are useful as hosts for the expression of proteolytically sensitive recombinant products. The isolation and characterization of additional genes from species of the genus Pichia is also described, as well as uses therefore.

Abstract: A transformation system is provided for C. tropicalis, comprising constructs and microorganisms, as well as methods for preparing constructs and microorganisms, and transforming microorganisms. Particularly, a yeast transformation system comprising auxotrophic hosts which are auxotrophic in either an amino acid, purine or pyrimidine pathways and employ DNA constructs comprising genes encoding biosynthetic enzymes which functionally complement the auxotrophies to prototrophies.