Fig. 7. Anlagen growth and chondrocyte proliferation are unaffected in
Ror2W749FLAG/W749FLAG embryos. (A,B)
Forelimb sections from Ror2+/W749FLAG (HET, A) and
Ror2W749FLAG/W749FLAG (KI, B) E13.5 embryos stained with
HAB reveal decreased cell numbers in the cartilagenous condensations of the
mutant limbs. Stylopod (s), zeugopod (z) and autopod (a) are indicated.
(C-F) High magnification of E13.5 ulna sections stained with HAB (C,E)
or HGF (D,F), showing normal cell density and intensity of matrix staining.
(G,H) Forelimb sections from Ror2+/W749FLAG
(G) and Ror2W749FLAG/W749FLAG (H) E15.5 embryos stained
with HAB and HGF. No overt histological alterations are observed in cell
density or matrix staining, but the Ror2W749FLAG/W749FLAG
bones are shorter, and have a smaller region of hypertrophy and primary
spongiosa. (I,J) Sections of E18.5 humeri from three individual
Ror2+/W749FLAG (I) and
Ror2W749FLAG/W749FLAG (J) embryos stained with an
anti-BrdU antibody and counterstained with AB.
Ror2W749FLAG/W749FLAG humeri have a reduced length and
shorter epiphyses (epiphysis range is indicated with horizontal lines). No
difference was observed in the density or distribution of BrdU-positive cells.
(K-N) BrdU incorporation analysis in E12.5 digital rays (K,L) and
proliferative zone of postnatal P5 femurs (M,N, zone delineated) from
Ror2+/W749FLAG (HET) and
Ror2W749FLAG/W749FLAG (KI) littermate mice. (K,L)
Proliferative rates were assayed in E12.5 rays by measuring the number of
BrdU-positive nuclei (red) relative to the total number of nuclei (blue) in
the condensation. No significant difference was observed between the genotypes
(12.2±0.04% versus 12.5±0.05% in the controls,
P=0.069). (M,N) BrdU incorporation analysis in postnatal P5 femurs
showed no significant difference between genotypes (383±41.9 versus
373±60.5 cells/mm2 in the controls, P=0.90).
(O,P) High magnification of the growth plates from the sections
shown in M and N, respectively, revealing a normal architecture of the
columnar chondrocytes.