Yesterday we wrapped up a workshop "Genome editing in zebrafish: knock-ins and their applications". A huge THANK YOU to EVERYONE who joined us for very rigorous and stimulating scientific discussion throughout the workshop! (1/5)
Rapid generation of single-insertion #transgenics by #Tol2 transposition in #zebrafish. This study describes modifications to Tol2-mediated transgenesis that facilitates the generation of multiple independent single-insertion F1 transgenic lines https://t.co/GKdpvESYRM
@sumeetpalsingh8 I was not trying to argue against I-SceI. It can be great in some scenarios like various "bow" applications you highlighted. With regard to Tol2, I believe one should only use single-copy lines in publications but I am clearly in a minority.
1/8 Are you interested in knocking genes out in adult zebrafish? If so, you should read our new preprint! Our new ~ubiquitous ubbR:CreERT2 driver enables gene knockout in adult #zebrafish hearts with efficiency approaching 100%. Yes, we quantified it. https://t.co/K5RoOj4XA1
@chrmosimann @sumeetpalsingh8 There is no practical way to prove near-100% efficient recombination in every possible cell type. When induced at 6 hpf and assessed at 3 dpf by qPCR on DNA, our driver gives better excision of ubi:Swi GFP than ubi:CrERT2 you went to great lengths to demonstrate was ubiquitous.
@chrmosimann @sumeetpalsingh8 That is why we quantify excision at DNA level. It is certainly NOT perfect, but it does tell us that excision occurs in absolute majority of cells in a complex tissue like the adult ventricle.
@sumeetpalsingh8 As for I-SceI vs Tol2, my impression is that with I-SceI one often - if not mostly - gets a concatemer in instead of single copy. Am I wrong?
@sumeetpalsingh8 Thank you for bringing your paper to my attention! We have other transgenics using the same carp actb2 that are super strong. Something about that particular transgene is just "funny". Even lens RFP is weaker. We re-made the plasmid, sequenced everything, and re-made transgenics.
8/8 - While we did not do a proper comparison our observations suggest that it is best to place the two loxP sites close together when making a #floxed allele. Similar observations have been made in other systems.
7/8 - Carp bAct2 did not seem to work at all in our docking site (line tpl102 @ZFINmod). However, its enhancer still boosted the expression of ubb. Is that strange or not?