1. Lecture 21 Retroviral vector method

2. A retrovirus is a virus that carries its genetic material in the form of RNA rather than DNA. A retrovirus is a virus that carries its genetic material in the form of RNA rather than DNA. as vectors to transfer genetic material into the host cell as vectors to transfer genetic material into the host cell resulting in a chimera, an organism consisting of tissues or parts of diverse genetic constitution resulting in a chimera, an organism consisting of tissues or parts of diverse genetic constitution chimeras are inbred for as many as 20 generations until homozygous (carrying the desired transgene in every cell) transgenic offspring are born chimeras are inbred for as many as 20 generations until homozygous (carrying the desired transgene in every cell) transgenic offspring are born

5. Figure.1 Establishing transgenic mice with retroviral vectors. Cleavage-Stage embryos, usually at the eight-cell stage, are infected with a defective retrovirus carrying a transgene. Implanted females (foster mothers) give birth to transgenic pups. Matings are carried out to determine which pups have the transgene in their germ line cells. Transgenic lines can be established from these founder transgenic animals.

6. Retroviral vector method Advantage: effective means of integrating the transgene into the genome of a recipient cell. Advantage: effective means of integrating the transgene into the genome of a recipient cell. Disadvantages: Disadvantages: can transfer only small pieces (approximately 8 kilo bases) of DNA can transfer only small pieces (approximately 8 kilo bases) of DNA lack essential adjacent sequences for regulating the expression of the transgene. lack essential adjacent sequences for regulating the expression of the transgene. the genome of the retroviral strain (helper virus) that is needed to create large quantities of the vector DNA can be integrated into the same nucleus as the transgene the genome of the retroviral strain (helper virus) that is needed to create large quantities of the vector DNA can be integrated into the same nucleus as the transgene