Distribution of β subunit subtypes in mouse cerebellum.
A, Splice variant-specific antibodies were created
against unique β4a and β4b
sequences (highlighted). B, Western blot showing that
β4a-, β4b-, and
β3-specific antibodies recognize 52–55 kDa proteins in
sucrose step gradient-purified mouse cerebellar membranes. Numbers to the left
indicate molecular mass in kilodaltons. C, Purkinje
cells labeled with anti-calbindin antibody (scale bar, 20 μm) serve to
distinguish the molecular (ML), Purkinje cell (PCL), and granule cell (GCL) layers
(for orientation in D–G).
D, E, Punctate
labeling of the β4a subunit in the molecular layer of
the cerebellum: D, confocal microscopy,
1-μm-thick image; E, light microscopy,
50-μm-thick section. F, The
β4b subunit is expressed in Purkinje cell bodies and
Bergman glia. G, The β3 subunit is
expressed in basket cell structures surrounding Purkinje cell bodies and in granule
cell layer puncta. Inset, Higher-power image (scale bar, 10 μm) of basket cell
labeling (supplemental Fig. 2, available at
www.jneurosci.org as
supplemental
material).