study in Nature Cell Biology finds that they play a previously little known role in gene regulation—a role that may influence some cancer cells’ responsiveness to different treatment types.

Prior to this study, some researchers thought the speckles—first discovered in the early 1900s—were “just kind of hanging out” in the nucleus, says lead author Katherine Alexander, a molecular and cell biologist at Cold Spring Harbor Laboratory in Long Island, New York. Speckles were known to contain RNA splicing machinery and other components needed for transcription and translation, but their behavior in the nucleus was not well understood. Alexander’s initial question was whether speckles are all the same from cell to cell or if there’s some variation—and what that may mean.