Transgenic Production of a Variant of Human Tissue-Type Plasminogen Activator in Goat Milk: Generation of Transgenic Goats and Analysis of Expression

Abstract

We report the first successful production of transgenic goats that express a heterologous protein in their milk. The production of a glycosylation variant of human tPA (LAtPA--longer acting tissue plasminogen activator) from an expression vector containing the murine whey acid promoter (WAP) operatively linked to the cDNA of a modified version of human tPA was examined in transgenic dairy goats. Two transgenic goats were identified from 29 animals born. The first animal, a female, was mated and allowed to carry the pregnancy to term. Milk was obtained upon parturition and was shown to contain enzymatically active LAtPA at a concentration of 3 micrograms/ml.

Sequencing and automated whole-genome optical mapping of the genome of a domestic goat (Capra hircus)

“…org/corp/statistics/en/). In addition to their value as domestic animals, goats are now used as animal models for biomedical research, to investigate the genetic basis of complex traits and in the transgene production of peptide medicines 4,5 . Despite the agricultural and biological importance of goats, breeding and genetics studies have been hindered by the lack of a reference genome sequence.…”

Transgenesis in the rat and larger mammals.

“…In sheep however, similar high levels of heterologous protein were expressed in milk over consecutive lactations and over several generations in a given transgenic line, allowing the viable development of a flock of transgenic sheep. In separate studies high levels of expression of human tissue plasminogen activator were obtained in goat's milk under the control of the goat ␤ -casein promoter (28). The development of suitable purification methods and the use of transgenically produced proteins in clinical trials are well advanced, and, if successful, will have important implications for the production of human proteins in transgenic livestock.…”

Genetic Modification of Domestic Animals for Agriculture and Biomedical Applications

“…Recombinant proteins, including human von Willebrand factor (Lee et al, 2009), human erythropoietin (Park et al, 2006), human insulin-like growth factor-I (Monaco et al, 2005), human factor VIII (Paleyanda et al, 1997) and bovine alpha-lactalbumin (Bleck et al, 1998) have been produced in the milk of transgenic pigs. Transgenic goats, capable of synthesizing human butyrylcholinesterase (Huang et al, 2007) and human longer acting tissue plasminogen activator (Ebert et al, 1991) in their milk have also been created. Human salmon calcitonin in milk of transgenic rabbits (McKee et al, 1998); human factor IX and alpha-1-antitrypsin (Wright et al, 1991) in milk of transgenic sheep; and human lactoferrin (van Berkel et al, 2002;Yang et al, 2008), human growth hormone (Salamone et al, 2006) and human -lactalbumin in milk of transgenic cows are all additional examples of using transgenic domestic animals and the mammary gland as a bioreactor for production of recombinant proteins.…”