Fig. 3. rem encodes one of two Drosophila Cks gene homologs. (A) Alignment of Drosophila Cks30A (Remnants) with Cks from other organisms. * indicates residue P61 altered in Cks30A^RA74 and Cks30A^HG24. + indicates residues implicated in Skp2 binding (S/T41,N45) for human Cks1. (B) Phylogenetic reconstruction (MacVector Neighbor Building Best Tree) does not permit assignment of Drosophila Cks proteins as orthologs of vertebrate Cks1 and Cks2, respectively. (C) Developmental northern blot probed for Cks30A and Cks85A reveals that Cks30A is mainly expressed in ovaries and embryos. Low concentrations are detected in third instar larvae and pupae. Cks85A is found at all stages examined. (D) Western blot from 0-2 embryos from wild type, Cks30A^KO/Cks30A^KO and Cks30A^HG24/Cks30A^HG24 probed with anti-Cks30A antiserum reveals a single band in wild-type and Cks30A^HG24 mutants, but no protein in Cks30A^KO.