CENTROMERE SEQUENCES LOCALIZE TO THE NUCLEAR HALO OF HUMAN SPERMATOZOA

Chromatin is organized into a series of discrete nuclear matrix-associ ated and non-nuclear matrix-associated domains. The non-matrix-associa ted domains consist of loops of DNA that are attached to the proteinac eous nuclear matrix by matrix-associated regions (MARs). Although this organization is well characterized in somatic cells, comparatively li ttle is known of this mode of organizing the genome in the human sperm nucleus. To define this relationship, the interaction of human sperm chromatin with the nuclear matrix was assessed by fluorescence in situ hybridization using specific alpha satellite probes directed to the c entromeric regions of chromosomes 13 plus 21 and 18. Hybridization of the centromeric sequences was visualized as segmented, bundled structu res that extended from the nuclear core into the halo.