Transgenic animal technology has been one of the fastest growing biotechnology areas. The exogenous genes have been introduced into the animal genome by genetic engineering, so that these genes can be inherited and ex...Transgenic animal technology has been one of the fastest growing biotechnology areas. The exogenous genes have been introduced into the animal genome by genetic engineering, so that these genes can be inherited and expressed by offspring to produce desired traits or evaluate function in elite livestock breeds. There are several methodologies for the production of transgenic animals, i.e., （1） microinjection of genes into pronuclei of fertilized ova; （2） DNA transfer by retroviruses; （3） injection of embryonic germ （EG）/embryonic stem （ES） cells previously treated with foreign DNA; （4） DNA transfer into cells and embryos with using liposomes; （5） exogenous DNA transfer while in vitro fertilization by using sperm; （6） electroporation of DNA into sperm, embryos or ova; （7） biolistics; （8） nuclear transfer （NT） with somatic cells, EG or ES cells; （9） germ line stem cell-mediated; （10） gene targeting; （! 1） gene silencing technology with RNA interference; （12） induced pluripotent stem cell; （13） zinc-finger nuclease gene targeting technology. Gene farming is one of the newest and most promising areas in modern biotechnology. Cattle, goats, sheep, pigs and rabbits are the main farm livestock species and fish is also used in transgenic technology. The question of ＂why make transgenic animals？＂ is very important. Some of the answers to this question are： （1） to obtain new knowledge; （2） to solve the genetic code; （3） to create genetic disease models; （4） to study the genetic control of physiological systems; （5） to improve animal production traits; （6） to produce new animal products. Transgenic technology is one of the main and important tools in the finding solutions to problems of growing population with their applications to different organisms, and takes more attention and interest every day. Transgenic technology creates opportunities and areas to play with organisms to fulfill the demands of people. Because of this, this paper based on mainly transgenic applications to take people＇s attention and exhibit its importance.展开更多
Medium-chain-length-polyhydroxyalkanoates (mcl-PHAs) belong to the group of microbial polyesters con- taining monomers ranging from 6 to 14 carbons in length. The key enzymes of their biosynthesis are PHA-polymerase (...Medium-chain-length-polyhydroxyalkanoates (mcl-PHAs) belong to the group of microbial polyesters con- taining monomers ranging from 6 to 14 carbons in length. The key enzymes of their biosynthesis are PHA-polymerase (product of phaC gene) and 3-hydroxyacyl-acyl carrier pro- tein-CoA transferase (product of phaG gene). With aadA (aminoglycoside 3′-adenylyltransferase) gene as screening marker, two chloroplast transformation vectors of pTC2 harboring phaC2 gene only and pTGC harboring both phaC and phaG genes were constructed and introduced into to- bacco chloroplast genome through particle bombardment. PCR and Southern blot analysis confirmed the insertion of the introduced genes into chloroplast genome. The content of mcl-PHAs accumulated in transgenic plants was analyzed by gas chromatography, mcl-PHAs accumulated up to 4.8 mg/g dry weight (dw) in transgenic line S4-3; their monomers were 3-hydroxyoctanoate and 3-hydroxydecanoate. Accumulation of mcl-PHAs polymers in the tobacco chloroplast was also observed by transmission electron microscopy. To our knowledge, this is the first report on the synthesis of mcl- PHAs in tobacco via chloroplast genetic engineering.展开更多
文摘Transgenic animal technology has been one of the fastest growing biotechnology areas. The exogenous genes have been introduced into the animal genome by genetic engineering, so that these genes can be inherited and expressed by offspring to produce desired traits or evaluate function in elite livestock breeds. There are several methodologies for the production of transgenic animals, i.e., （1） microinjection of genes into pronuclei of fertilized ova; （2） DNA transfer by retroviruses; （3） injection of embryonic germ （EG）/embryonic stem （ES） cells previously treated with foreign DNA; （4） DNA transfer into cells and embryos with using liposomes; （5） exogenous DNA transfer while in vitro fertilization by using sperm; （6） electroporation of DNA into sperm, embryos or ova; （7） biolistics; （8） nuclear transfer （NT） with somatic cells, EG or ES cells; （9） germ line stem cell-mediated; （10） gene targeting; （! 1） gene silencing technology with RNA interference; （12） induced pluripotent stem cell; （13） zinc-finger nuclease gene targeting technology. Gene farming is one of the newest and most promising areas in modern biotechnology. Cattle, goats, sheep, pigs and rabbits are the main farm livestock species and fish is also used in transgenic technology. The question of ＂why make transgenic animals？＂ is very important. Some of the answers to this question are： （1） to obtain new knowledge; （2） to solve the genetic code; （3） to create genetic disease models; （4） to study the genetic control of physiological systems; （5） to improve animal production traits; （6） to produce new animal products. Transgenic technology is one of the main and important tools in the finding solutions to problems of growing population with their applications to different organisms, and takes more attention and interest every day. Transgenic technology creates opportunities and areas to play with organisms to fulfill the demands of people. Because of this, this paper based on mainly transgenic applications to take people＇s attention and exhibit its importance.
基金the National 863 Program of China(Grant No.2002AA213051).
文摘Medium-chain-length-polyhydroxyalkanoates (mcl-PHAs) belong to the group of microbial polyesters con- taining monomers ranging from 6 to 14 carbons in length. The key enzymes of their biosynthesis are PHA-polymerase (product of phaC gene) and 3-hydroxyacyl-acyl carrier pro- tein-CoA transferase (product of phaG gene). With aadA (aminoglycoside 3′-adenylyltransferase) gene as screening marker, two chloroplast transformation vectors of pTC2 harboring phaC2 gene only and pTGC harboring both phaC and phaG genes were constructed and introduced into to- bacco chloroplast genome through particle bombardment. PCR and Southern blot analysis confirmed the insertion of the introduced genes into chloroplast genome. The content of mcl-PHAs accumulated in transgenic plants was analyzed by gas chromatography, mcl-PHAs accumulated up to 4.8 mg/g dry weight (dw) in transgenic line S4-3; their monomers were 3-hydroxyoctanoate and 3-hydroxydecanoate. Accumulation of mcl-PHAs polymers in the tobacco chloroplast was also observed by transmission electron microscopy. To our knowledge, this is the first report on the synthesis of mcl- PHAs in tobacco via chloroplast genetic engineering.
