Dynamic variations in the expression of type I collagen and its molecular chaperone Hsp47 in cells of the mouse dental follicle during tooth eruption.
Tooth eruption is a precisely timed and sequenced event that brings the tooth from within bone into a functional position in the mouth. Every part of the developing tooth has been theoretically implicated as a primary factor in this process, but it now appears that eruption is multifactorial, with the dental follicle and type I collagen playing an important part. Immunological probes were used here to investigate in vivo and in vitro the temporal and spatial expression of type I collagen and its molecular chaperone Hsp47 in the dental follicle during eruption. Mandibles were dissected from 2-, 5-, 9- and 11-day-old neonatal mice and fixed in 95% ethanol overnight. Sections of 7 microns were obtained and reacted with antibodies directed against type I collagen. Dental follicles were isolated from 2-, 5-, 9- and 11-day-old neonates and cells were grown in culture for 8 days. Slides were then reacted with antibodies directed against type I collagen and Hsp47. The production of type I collagen and Hsp47 in the follicle varied with the stage of dental development and eruption. There was a progressive decrease of type I collagen in the coronal part of the follicle, leading to an arrest of its production in these areas. These findings support the notion that cells of the coronal portion of the dental follicle stop producing type I collagen as a prerequisite to the initiation of tooth eruption and that this phenotype persists in vitro.
Department of Orthodontics, University of Maryland Dental School, Baltimore 21201.
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B
Shroff
R
R
Pileggi
K
K
Norris
R
R
Orbegoso
T
T
Wilson
J J
JJ
Sauk
D000818:Animals; D003094:Collagen / Q000235:genetics*; D046508:Culture Techniques; D003593:Cytoplasm / Q000378:metabolism / Q000648:ultrastructure; D003739:Dental Cementum / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D003795:Dental Sac / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D005347:Fibroblasts / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D050958:HSP47 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000235:genetics*; D051379:Mice; D008963:Molar; D009805:Odontogenesis / Q000235:genetics; D014078:Tooth Eruption / Q000235:genetics*; D014083:Tooth Germ / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure
D050958:HSP47 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C494661:Serpinh1 protein, mouse; D003094:Collagen