Figure 6.

Skin innervation in control, Runx1 CKO, and Zfp521 CKO mice. A, Hairy skin innervation of VGLUT3 lineage neurons in P60 control mice (ROSA26^Tomato/+;Vglut3^Cre/+). Left, Innervation of Tomato⁺ fibers surrounding a cluster of hairs in the skin “Area 1,” with the arrowhead indicating epidermal (“epi.”) innervation and the arrow indicating the neck region of a hair follicle. Right, Skin “Area 2” in which VGLUT3-Tomato⁺ fibers only form the “LLEs” (large arrowhead) without innervation to the skin epidermis (small arrowhead). B, Hairy skin innervation of VGLUT3 lineage neurons in P60 Runx1 CKO mice (Runx1^F/F;ROSA26^Tomato/+;Vglut3^Cre/+). Arrow in left panel indicates normal innervation to the hair follicle neck region of the skin “Area 1”; arrowhead indicates normal epidermal innervation. For the right panel, large arrowhead indicates Tomato⁺ fibers being converted from LLEs to circumferential endings (“C.E.”) in skin “Area 2”; arrows indicate fibers growing toward skin surface and terminating the epidermis (small arrowhead). There was no typical innervation to the hair neck (B, right). C, The innervation pattern was not changed in Zfp521^F/F;ROSA26^Tomato/+;Vglut3^Cre/+ CKO mice compared with wild-type controls (A), including: (1) the retaining of “LLEs” (large arrowheads) and (2) restricted innervation to the skin epidermis (small arrowhead, left) and the neck region (arrow, left) only around a small subset of hairs (“area 1”), but not around most hairs (“area 2”). Scale bars, 50 μm.