Mouse amelogenin exons 8 and 9: sequence analysis and protein distribution.
Amelogenin is the major protein of the developing enamel. Two additional exons, termed 8 and 9, have been characterized in the rat. Our aim was: to identify the mouse amelogenin exons 8/9 sequences; to investigate the potential presence of the alternative spliced isoforms of amelogenin exons 8/9; and to immunolocalize proteins containing sequences encoded by exons 8/9 during odontogenesis. RT-PCR analysis with exon 9 anti-sense primer generated 2 major amplicons with the use of a mouse tooth cDNA library and dental cell lines. DNA sequence analysis showed 93% identify with the rat exons 8/9 sequence. Alternative splicing of exon 3 was also found, but only in cDNAs lacking exons 8 and 9. Immunohistochemistry localized exons 8/9-encoded proteins in ameloblasts, young odontoblasts, and stratum intermedium cells. Analysis of our data supports the hypothesis that: (1) AMELX contains 2 additional exons; (2) ameloblasts and odontoblasts synthesize amelogenin 8/9; and (3) amelogenin splice variants may have unique functions during tooth formation.
Department of Pediatric Dentistry, Dental School, University of Texas Health Science Center San Antonio, MSC 7888, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
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P
Papagerakis
J M
JM
Ibarra
N
N
Inozentseva
P
P
DenBesten
M
M
MacDougall
D017398:Alternative Splicing / Q000235:genetics; D000565:Ameloblasts / Q000378:metabolism*; D053523:Amelogenin; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000032:analysis; D003746:Dental Enamel Proteins / Q000235:genetics* / Q000378:metabolism*; D005091:Exons / Q000235:genetics; D015723:Gene Library; D007150:Immunohistochemistry; D051379:Mice; D008969:Molecular Sequence Data; D009804:Odontoblasts / Q000378:metabolism*; D012313:RNA / Q000032:analysis; D017422:Sequence Analysis, DNA; D014018:Tissue Distribution; D014083:Tooth Germ / Q000166:cytology / Q000378:metabolism*
D053523:Amelogenin; C507200:Amelx protein, mouse; C507201:Amelx protein, rat; D003746:Dental Enamel Proteins; D012313:RNA; D004247:DNA