Positional changes of pericentromeric heterochromatin and nucleoli in postmitotic Purkinje cells during murine cerebellum development

Previous studies revealed changes of pericentromeric
heterochromatin arrangements in postmitotic Purkinje cells (PCs)
during postnatal development in the mouse cerebellum (Manuelidis,
1985; Martou and De Boni, 2000). Here, we performed vibratome
sections of mouse cerebellum (vermis) at P0 (day of birth), at
various stages of the postnatal development (P2-P21), as well as in
very young (P28) and 17-months-old adults. FISH was carried out on
these sections with major mouse satellite DNA in combination with
immunostaining of the nucleolar protein B23 (nucleophosmin). Laser
confocal microscopy, 3D reconstructions and quantitative image
analysis were employed to describe changes in the number and
topology of chromocenters and nucleoli. At all stages of postnatal
PC development heterochromatin clusters were typically associated
either with nucleoli or with the nuclear periphery, while
non-associated clusters were rare (