The PiggyBAC Transposon: Generating Transgenic Mice with Consistent Expression

In the last video which you can find right here, ( • The Basics of Transgen... ) we talked about what transgenic mice are and how they are developed by scientists using a traditional pronuclear injection. However, there are some limitations to using the pronuclear injection method to create a transgenic animal.
In order to obtain transgenic mice scientists must inject many zygotes with the transgene before implanting them into a surrogate mother. Although the majority of them will die, each one of them possesses the potential to turn into its own transgenic mouse. In a Traditional pronuclear injection, each of these zygotes will undergo a totally random integration of the transgene. This will lead to great varieties in the expression level of the offspring.
This is great right? We should have a high expression of the transgene in individuals because so many copies have been integrated. Well not exactly. At some loci, These tandem repeats may increase the expression of the target gene, while at others, the tandem integration silences the expression of the gene itself.
The different locations that the transgene may integrate into on the chromosome may play a part in explaining the variability of the gene expression as well. Just like random integration means random number of copies, it means random location as well. If the dna integrates into an area of closed chromatin this will lead to a lower frequency of expression than if other, ore open sites on the chromosome.
For this reason, scientists have used the Piggyback transposon for over a decade as a way to generate Transgenic mice with single copy integration into areas of open chromatin. In the traditional approach used to generate transgenic mice, tandem integration often leads to variable levels of gene expression. Some individuals have medium expression and some have none at all. Using piggyback to generate transgenic mice leads to high and consistent expression of the transgene across all F1 individuals.
Watch this video to learn about how it leads to a higher, more consistent expression by discovering what it means to integrate into open TTAA site, chromatin.
Use code watch-T in your inquiry for any of our transgenic mouse services which can be found here for 15% off for a limited time:
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In most experiments, scientists will try to minimize the amount of independent variables so as not to confuse the results of an experiment. Unless the level of gene expression is the variable that the scientist hopes to study, using the offspring from a transgenic mouse created via traditional pronuclear injection may not be the best option.
Some images in this video were created with Biorender.
Sources:
Handler, A. M., McCombs, S. D., Fraser, M. J., & Saul, S. H. (jun 1998). The lepidopteran transposon vector, piggyBac, mediates germ-line transformation in the Mediterranean fruit fly. Proceedings of the National Academy of Sciences. doi:10.1073/pnas.95.13.7520
Lantz, N. (Director). (2018, October 11). Introduction to Transposons [Video file]. Retrieved February 5, 2021, from • Introduction to Transp...
PiggyBac transgenic mice. (n.d.). Retrieved February 09, 2021, from www.cyagen.com/us/en/service/...
Piggybac transposon system. (2020, February 24). Retrieved February 09, 2021, from www.herabiolabs.com/piggybac-...
Rülicke, T., & Hübscher, U. (2004, May 05). Germ line transformation of mammals by PRONUCLEAR MICROINJECTION. Retrieved February 09, 2021, from physoc.onlinelibrary.wiley.co...
Woodard, L. (Director). (2019, December 4). PiggyBac Transposons to Cut and Paste DNA [Video file]. Retrieved February 5, 2021, from www.youtube.com/watch?reload=...
Zhao, S., Jiang, E., Chen, S., Gu, Y., Shangguan, A. J., Lv, T., . . . Yu, Z. (2016). PiggyBac transposon vectors: The tools of the human gene encoding. Translational Lung Cancer Research, 120-125. doi:10.3978/j.issn.2218-6751.2016.01.05
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[@shawnchamberlain8543]

Thank you, very nice video!

[@samirbrahimi5782]

great explanations

[@user-xe5wo6tn8u]

Thank you so much.

[@oliwiazagorska9977]

Great animation! very useful

[@soniakhan9472]

Will the resultant mice be heterozygous for the knocked-in gene?

[@firdawsnesrinemahboubi4519]

i would like to see more videos about transgenes

[@mgold9999]

Nice video! How many copies of the gene will be inserted in the genome at different places? How many PiggyBac plasmids are injected? How many TTAA/AATT sites are there in the genome?

[@user-uj8og9cm9d]

I'm curious about this as well, I'm assuming each transposition event is quite rare but there are probably an insanely high number of TTAA sites in the genome so it wouldn't surprise me if you sometimes find multiple insertions.

[@tammora8]

how did you make this animation, which program? thanks

[@kieulinhho8969]

CovidImages need to be invested more than half19