S2 STOCKS IN THE DGRC COLLECTION
Imogen Schneider established 3 cell lines in 1972; they are commonly referred to as S1, S2, and S3, but each is also called by a number of synonyms (e.g. SL2, Schneider 2, DMel2, and corresponding synonyms for lines 1 and 3). Schneider distributed these cells widely to the community, especially S2, and no one kept careful track of the history of the cells that they used. S2, like all tissue culture lines, gradually changes as it is grown; such changes accumulate especially when the cells are grown for a long period of time and when they are exposed to stresses. As a result, the S2 cells in different labs differ to some extent. Once a cell line enters the DGRC collection, it is grown for only the shortest time needed to make new frozen stocks as needed, with the intent of minimizing the variation accumulated during the line's residence in our collection.
To help users who are trying to decide which isolate is best suited for their experimental purposes, we provide a brief description of each isolate below, and links to references in which each isolate was used for specific applications.
S2-DGRC (stock #6) When the DGRC was established in 2004, our original cell line collection included many lines that were simply transferred from the Cherbas lab collection; among these were S2 cells (stock #6), which we simply referred to as "S2". These cells were a gift from Cheeptip Benyajati to the Cherbas lab around 1980; we have no knowledge of their earlier history. In 2016, after it became obvious that the literature contained many reference to S2, some of which were the S2 cells distributed by the DGRC, some were other isolates, and some were of unknown origin, we renamed our stock #6 as S2-DGRC, in order to distinguish them from other S2 isolates. Note: This line is named for the DGRC (Drosophila Genomics Resource Center).
S2-DRSC (stock #181) At the beginning of the modENCODE project, it was desirable to designate a single S2 isolate to be used throughout the project and by members of the community who wished to take advantage of modENCODE-produced data; the desired attributes of this isolate were that it be easy to culture and known to be sensitive to RNAi treatment. For this purpose, Norbert Perrimon donated to the DGRC the isolate of S2 cells that were used for RNAi-based screens at the DRSC; we named this isolate S2-DRSC. Perrimon had received S2 cells from several labs (including the Cherbas lab), and the relationship between S2-DRSC and S2-DGRC is unknown. Note: This line is named for the DRSC (Drosophila RNAi Screening Center).
Sg4 (stock #179) This is a clone made by Donna Arndt-Jovin from S2 cells of unknown source. It has been used extensively in the Pirrotta laboratory because of its strong expression of Abd-B, not seen in our other S2 isolates.
S2R+ (stock #150) These cells were given by Imogen Schneider to Tadashi Miyake soon after the establishment of the original S2 line, and were stored frozen for most of the next 50 years. An aliquot of the cells was thawed by Yanagawa in the 1990s and found to express a receptor for Wingless, unlike other S2 cells that had been tested. He gave it the name S2R+, where R+ refers to the expression of Wingless receptor. Because of its history, we suspect that these cells are more similar to the original line established in the Schneider laboratory than any of the other S2 isolates in our collection.