Patterns of expression of Hoxa-11 in micromass cultures of chick limb mesenchyme from various stages suggest a role for Hoxa-11 in the specification of the zeugopod.
During chick limb development the expression of Hoxa-11 specifically associated with the prospective zeugopod (radius + ulna) region. A series of micromass cultures were performed using mesenchyme from whole stage 18/19 or 20/21 limbs or mesenchyme from the tips of stage 22/23, 23/24 or 25 limbs. In such cultures, limb mesenchyme undergoes chondrogenesis paralleling its fate in vivo. Hoxa-11 and collagen type II mRNA were examined by dot blot and in situ analysis at different time points. The highest level of Hoxa-11 mRNA was found in micromass cultures of the tips of stage 22/23 and 23/24 limbs at 48 hours. Between stages 22 and 24, the determining events occur which subsequently lead to the formation of the zeugopod by the mesenchyme present in the tips at these stages. This correlation further supports a possible role of Hoxa-11 in the specification of the zeugopod.
Rogina
B
B
Department of BioStructure and Function, School of Dental Medicine, University of Connecticut Health Center, Farmington 06030-3705, USA.
D000818:Animals; D002356:Cartilage / Q000196:embryology* / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D002642:Chick Embryo; D003094:Collagen / Q000096:biosynthesis / Q000235:genetics; D005121:Extremities / Q000196:embryology; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D017403:In Situ Hybridization; D008648:Mesoderm / Q000378:metabolism*; D009024:Morphogenesis / Q000235:genetics; D009924:Organ Culture Techniques; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
D018398:Homeodomain Proteins; D012333:RNA, Messenger; D003094:Collagen