Fig. 2. Misexpression of Nkx3.2 inhibits chondrocyte maturation. The right wing buds of late E3 chick embryos (HH stage 16-18) were infected with RCAS(A)-Nkx3.2. The embryos were harvested on E9, and processed for Alcian Blue/Alizarin Red staining (A), or pulsed for three hours with BrdU prior to harvesting on E10 for ISH and BrdU incorporation (B,C). Red arrowhead (A) indicates the nascent bone collar. Double-headed arrows (B) compare the peripheral-most extent of Ihh and col X expression in the RCAS-Nkx3.2-infected and contralateral control wings. Arrowhead (C) indicates the approximate boundary between proliferative and non-dividing cells in the cartilage of the control wing; arrows indicate proliferative cells in central regions of the RCAS-Nkx3.2-infected wing cartilage. hu, humerus; ra, radius; ul, ulna.