In this study, researchers showed that, in HeLa cells which derived from cells of a person who had cervical cancer and have proven useful for experiments, the first group of spliceosomes on pre-mRNA come from these speckles. Researchers used microinjections of spliceosome-accepting and mutant adenovirus pre-mRNAs with differential splicing factor binding to make different groups and then followed the sites in which they were heavily present. Spliceosome-accepting pre-mRNAs were rapidly targeted into the speckles, but the targeting was found to be temperature-dependent.