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Advanced Gene Technology. DNA,RNA, Recombinant DNA Technology. Nucleic Acids – DNA and RNA. DNA + RNA. DNA + RNA. DNA + RNA. RNA. DNA. DNA structure -> sequence. Polymerase reaction: 5’-> 3’. The central dogma. Page 93. Gene expression. Page 93. What is a gene?.
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DNA + RNA DNA + RNA DNA + RNA RNA DNA
Polymerase reaction: 5’-> 3’
The central dogma Page 93
Gene expression. Page 93
Eukaryotes – Intron-Exon concept Page 95
DNA mRNA Ribosome Polymerase Protein
Recombinant DNA Technology Clones -> Cells or organisms with identical DNA
Restrictionendonucleases 5’-> 3’ 3’ <- 5’
X-Ray structure of a complex of ethidium bromid with DNA. Page 1125
Construction of a restriction map. Page 104
Restriction map for the 5243-bp circular DNA of SV40. Page 104
Construction of a recombinant DNA molecule through the use of synthetic oligonucleotide adaptors Page 109
Ligation conditions • Temperature: 4º-10ºC -> takes long time 16ºC -> good temperature, but maybe inconvenient RT (room temp) -> much faster, compromise • Concentration of DNA : high -> intermolecular (between different molecules) ligation fevered low -> intramolecular (within one molecule) ligation fevered • Optimal vector-insert ratio: from 1:3 to 3:1 (molar ratio -> vector: insert) depending on size e.g.: vector: 5kb + insert: 500 bp -> molar ratio of 1:1 -> 500ng vector + 50 ng insert vector: 6kb + insert: 50kb -> 1:1 -> 500ng vector + 5ug insert -> WV/SV:WI/SI
Insertional inactivation Gene in cloning site: • LacZ -> pUC18 (lacZ complements the host defect in lacZ) -> pUC18 into host organism -> active lacZ (β-galactosidase) from plasmid-> cleavage of X-gal (blue colonies) -> gene cloned into polylinker -> lacZ gene disrupted -> no cleavage of X-gal (white colonies)
Insertional inactivation Gene in cloning site: • Resistance marker -> pBR322 (cloning sites within antibiotica resistence marker) -> plasmid into host -> resistance against 2 antibiotica -> gene cloned within one resistance marker -> gene for antibiotica resistance marker disrupted -> sensitive against one antibioticum
Horizontal gene transfer • - Transformation -> uptake of naked DNA (chemical transformation, electroporation) • - Conjugation -> DNA transfer by cell – cell contact • Transduction -> DNA transfer by bacteriopage infection • Other methods of Gene transfer -> used with fungi, animal and plant cells: • Microinjection • protoplasts
Electron micrograph of bacteriophage λ. Bacteriophages Page 107 Electron micrograph of the filamentous bacteriophage M13.