Dear Seth and Rick,

FlyBase and the DGRC are collaborating on expanding the cell line references for both of our websites. We came upon a problem with your recent paper (Zhang et al. 2016 eLife 5:e16624 ). You used two cell lines in this paper; Cl.8 and a line which is referred to as S2R+, but linked in the methods section to the DGRC and Cellosaurus identifiers for S2R+-SQH-GFP. I am writing to check on the identity of the cell line used.

Thanks in advance for your help in this matter.

Lucy

Must be a clerical error, this was just plain vanilla S2R+.

Seth

Thanks for your quick response. I now have another small mystery for you. After I sent my last email I discovered a newer paper from the same collaboration (Matakatsu et al. 2017 JCB 216:265 ) just speaks of "S2 cells" throughout, without any more specific detail. Were those also S2R+ cells? If you don't know which S2 isolate they were, we can just assign the paper to FlyBase's "S2-unspecified".

Lucy

In fact, the S2 cells we used in this paper originally came from you, back in the days when I was a postdoc in Spyros’ lab!

Rick

Thanks, Rick,

This is easy. When the DGRC was started, long ago, I (on behalf of the Cherbas lab) donated a sample of our S2 cells to myself (representing the DGRC), and they because DGRC stock #6. This was a couple of years after the collaboration with you when you were at Yale. A few months back, at the suggestion of the FlyBase folks, we changed the name of this stock to "S2-DGRC" in an attempt to minimize confusion with all the other S2 stocks now in the DGRC collection and out in the community. They are still our stock #6, and I'd suggest that you refer to them in future publications as "S2-DGRC" so that they can be distinguished from the multitude of other S2 isolates that people are using. Of course, since they have been grown independently for so many years, I'm sure that they are no longer identical to our stock, but we just have to live with that level of uncertainty with both fly stocks and cell stocks.

I'm glad that that sample of cells is still alive and thriving and contributing to science!

Lucy