Nkx2-5 mutation causes anatomic hypoplasia of the cardiac conduction system
J. Clin. Invest. Patrick Y. Jay, et al. 113:1130 doi:10.1172/JCI19846 [
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Figure 4Cx40 immunohistochemistry confirms hypoplasia of the peripheral Purkinje system and normal cellular expression levels of Cx40 in
Nkx2-5+/– mice. Montage confocal images demonstrate Cx40 expression as red, punctate staining in the subendocardial Purkinje fibers of WT (A and C) and
Nkx2-5+/– (B and D) left ventricular myocardium. The distribution of Cx40 in the
Nkx2-5+/– myocardium is considerably smaller than in WT (arrows in A and B). Higher magnification images of the boxed areas in A and B reveal the increased thickness of Purkinje fiber layers (arrowheads) in the WT (C) compared with
Nkx2-5+/– heart (D). LV, left ventricle. Scale bars: 100 μm. (E) Cell counts within Cx40-positive domains reveal that Purkinje cell numbers are reduced by approximately half within sections of
Nkx2-5+/– ventricles (
P < 0.05). (F)
Nkx2-5+/– and WT Purkinje cells contain approximately the same the number of Cx40 particles per cell. Three hearts each from WT and
Nkx2-5+/– animals were examined.
