Cid in sperm is required for propagation of paternal chromosomes in progeny.

<p>During spermatogenesis, a GFP-specific ubiquitin ligase <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001434#pbio.1001434-Caussinus1" target="_blank">[32]</a> was either expressed (+ <i>deGrad cid-EGFP</i>) or not expressed (− <i>deGrad cid-EGFP</i>) in males producing only Cid-EGFP instead of normal Cid. (a) Analysis of their sperm and of early embryos obtained after mating the males with Cid-EGFP females revealed that GFP ubiquitin ligase expression resulted in effective Cid-EGFP depletion in sperm, inhibited maternal Cid-EGFP recruitment onto paternal centromeres, and abolished paternal centromere function during embryonic cycle 1. Centromeric Cid-EGFP signals detectable in − but not + <i>deGrad cid-EGFP</i> samples are indicated by green arrows. Chromosomes without Cid-EGFP signals that were not segregated to the poles of mitosis 1 spindles are indicated by white block arrows. (b) Analysis of − and + <i>deGrad cid-EGFP</i> progeny during early anaphase of syncytial blastoderm mitoses revealed in each half spindle eight sister centromeres in the former, as expected for diploid embryos, but only four (or rarely five) in the latter. White frames in top panels indicate regions shown at high magnification in bottom panels.