The Drosophila crooked neck (crn) gene encodes an unusual TPR-containing protein whose function is essential for embryonic development. Homology with other TPR-proteins involved in cell cycle control. initially led to the proposal that Crn might play a critical role in regulation of embryonic cell divisions. Here. we show that Crn does not have a cell cycle function in the embryo. By using specific antibodies we also show that the Crn protein is a nuclear protein which localizes in "speckles" which could correspond to preferential localization of several other splicing factors. Fractionation of nuclear extracts on sucrose gradients revealed Crn in a 900 kDa multiproteic complex together with snRNPs, suggesting that Crn participates in the assembly of the splicing machinery in vivo. (C) 2002 Elsevier Science (USA). All rights reserved.