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.
Papagerakis
P
P
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.
Ibarra
J M
JM
Inozentseva
N
N
DenBesten
P
P
MacDougall
M
M
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