Enviropig Step 1
The first step to Enviropig describes the process of gene design in preparation of transforming and breeding a transgenic organism.
For more information visit the Enviropig website: https://ge.unl.edu/enviropig/
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[00:00:07.171]Enviropigs were first designed to address
[00:00:11.391]the issue of environmental contamination
[00:00:13.952]caused by phosphorous in the manure of agricultural animals.
[00:00:18.913]Pigs and poultry have a lot of phosphorous in their manure
[00:00:23.775]and disposing of it is a huge environmental concern.
[00:00:32.295]My name is Rebecca Cederberg.
[00:00:33.715]I'm a Research Analyst in the Animal Science Department
[00:00:36.715]at the University Nebraska-Lincoln.
[00:00:39.055]I work in a reproductive physiology lab.
[00:00:43.617]I design transgenes that are used to better
[00:00:45.857]understand reproduction in pigs.
[00:00:48.959]All the information to make an organism
[00:00:51.059]is located in its DNA.
[00:00:53.659]DNA for mammalians have approximately 20,000 to 25,000 genes.
[00:00:58.904]A gene encodes a protein,
[00:01:01.325]and the protein either is necessary
[00:01:03.695]for a building block of the cell,
[00:01:06.226]or it is important for the cell's function.
[00:01:09.786]Every cell has a specific job,
[00:01:11.966]and so it only wants to, so it's not wasteful,
[00:01:15.606]produce the proteins necessary for its job.
[00:01:19.206]A gene really has two parts.
[00:01:21.087]It has the sequence that encodes the protein,
[00:01:24.107]and then the sequence that regulates
[00:01:26.207]when and where that protein is made.
[00:01:34.629]When you're designing a transgene it's important
[00:01:37.289]that the protein is produced in your cell of interest,
[00:01:40.389]so you need to have a promoter that is active
[00:01:42.629]in that cell type so your transgene can be produced.
[00:01:46.489]The trangene allows pigs to produce phytase in their saliva
[00:01:51.269]and break down the phytate in their feed.
[00:01:54.289]This is helpful or beneficial to the pigs
[00:01:56.389]because then they can utilize the phosphorous
[00:01:59.129]in their feed which they previously would not be able to.
[00:02:03.289]This reduces the amount of phosphorous pollution
[00:02:06.550]in their feces and cuts down on pollution.
[00:02:11.580]And also is beneficial because pigs
[00:02:15.555]normally require phosphorous additive in their feed.
[00:02:18.996]DNA code is universal.
[00:02:21.216]All organisms use the same four
[00:02:23.458]bases to encode their proteins,
[00:02:26.601]so the pig cells were able to read the transgene.
[00:02:30.982]The mouse parotid secretory protein promoter
[00:02:34.502]was used to make the transgene,
[00:02:37.682]and this caused the phytase gene to be expressed
[00:02:40.922]in the salivary gland of the pigs,
[00:02:43.082]allowing the phytase to be secreted into the saliva.
[00:02:46.822]The gene is from E. coli.
[00:02:48.982]E. coli regulate gene expression
[00:02:51.163]much differently than mammals,
[00:02:53.183]so it was important for the scientists
[00:02:54.583]to select a promoter that would allow
[00:02:56.463]the phytase gene to be expressed in the pig cells.
[00:03:00.123]DNA was isolated from mice and E. coli,
[00:03:03.843]and the sequence of interest was amplified using PCR.
[00:03:08.903]The fragments were run on an agarose gel electrophoresis,
[00:03:13.725]isolated and combined together with ligase.
[00:03:17.526]Once the transgene is produced in the laboratory,
[00:03:20.287]then it is given to the transformation scientist,
[00:03:23.007]who will integrate it into a pig embryo.
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