Amelogenin is the major enamel matrix component in developing teeth. In eutherian mammals, amelogenin is expressed from the X chromosome only, or from both the X and Y chromosomes. Two classes of porcine amelogenin cDNA clones have been characterized, but the chromosomal localization of the gene(s) encoding them is unknown. To determine if there are sex-based differences in the expression of porcine amelogenin, we paired PCR primers for exons 1a, 1b, 7a, and 7b, and amplified enamel organ-derived cDNA separately from porcine males and females. The results show that exons 1a/2a and 7a are always together and can be amplified from both males (XY) and females (XX). Exons 1b/2b and 7b are also always paired, but can be amplified only from females. We conclude that porcine amelogenin is expressed from separate genes on the X and Y chromosomes, and not, as previously proposed, from a single gene with two promoters.
Get full access to this article
View all access options for this article.
References
1.
Akane A, Seki S, Shiono H, Nakamura H, Hasegawa M, Kagawa M, et al. -1992-. Sex determination of forensic samples by dual PCR amplification of an X-Y homologous gene. Forensic Sci Int52:143–148.
2.
Chang YM, Burgoyne LA, Both K -2003-. Higher failures of amelogenin sex test in an Indian population group. J Forensic Sci48:1309–1313.
3.
Chen CM, Hu CL, Wang CH, Hung CM, Wu HK, Choo KB, et al. -1999-. Gender determination in single bovine blastomeres by polymerase chain reaction amplification of sex-specific polymorphic fragments in the amelogenin gene. Mol Reprod Dev54:209–214.
4.
Fincham AG, Belcourt AB, Termine JD, Butler WT, Cothran WC -1981-. Dental enamel matrix: sequences of two amelogenin polypeptides. Biosci Rep1:771–778.
5.
Fincham AG, Bessem CC, Lau EC, Pavlova Z, Shuler C, Slavkin HC, et al. -1991-. Human developing enamel proteins exhibit a sex-linked dimorphism. Calcif Tissue Int48:288–290.
6.
Fukae M, Tanabe T, Uchida T, Yamakoshi Y, Shimizu M -1993-. Enamelins in the newly formed bovine enamel. Calcif Tissue Int53:257–261.
7.
Hu C-C, Bartlett JD, Zhang CH, Qian Q, Ryu OH, Simmer JP -1996-. Cloning, cDNA sequence, and alternative splicing of porcine amelogenin mRNAs. J Dent Res75:1735–1741.
8.
Iwase M, Satta Y, Takahata N -2001-. Sex-chromosomal differentiation and amelogenin genes in mammals. Mol Biol Evol18:1601–1603.
9.
Iwase M, Satta Y, Hirai Y, Hirai H, Imai H, Takahata N -2003-. The amelogenin loci span an ancient pseudoautosomal boundary in diverse mammalian species. Proc Natl Acad Sci USA100:5258–5263.
10.
Kimura M -1980-. A simple method for estimating evolutionary rates of base substitution through comparative studies of nucleotide sequences. J Mol Evol16:111–120.
11.
Laemmli UK -1970-. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature227:680–685.
12.
Lagerström M, Dahl N, Nakahori Y, Nakagome Y, Bäckman B, Landegren U, et al. -1991-. A deletion in the amelogenin gene -AMG- causes X-linked amelogenesis imperfecta -AIH1-. Genomics10:971–975.
13.
Lahn BT, Page DC -1999-. Four evolutionary strata on the human X chromosome. Science286:964–967.
14.
Lau EC, Mohandas T, Shapiro LJ, Slavkin HC, Snead ML -1989-. Human and mouse amelogenin gene loci are on the sex chromosomes. Genomics4:162–168.
15.
Macdonald D, editor -1984-. The encyclopedia of mammals. New York: Facts on File, Inc.
16.
Marais G, Galtier N -2003-. Sex chromosomes: how X-Y recombination stops. Curr Biol13:R641–R643.
17.
Nakahori Y, Takenaka O, Nakagome Y -1991-. A human X-Y homologous region encodes amelogenin. Genomics9:264–269.
18.
Page RDM -1996-. TREEVIEW: an application to display phylogenetic trees on personal computers. Comput Appl Biosci12:357–358.
19.
Palmer S, Perry J, Kipling D, Ashworth A -1997-. A gene spans the pseudoautosomal boundary in mice. Proc Natl Acad Sci USA94:12030–12035.
20.
Perrière G, Gouy M -1996-. WWW-Query: an on-line retrieval system for biological sequence banks. Biochimie78:364–369.
21.
Saitou N, Nei M -1987-. The neighbor-joining method: a new method for reconstructing phylogenetic trees. Mol Biol Evol4:406–425.
22.
Salido EC, Yen PH, Koprivnikar K, Yu L-C, Shapiro LJ -1992-. The human enamel protein gene amelogenin is expressed from both the X and Y chromosomes. Am J Hum Gen50:303–316.
23.
Simmer JP, Snead ML -1995-. Molecular biology of the amelogenin gene. In: Dental enamel: formation to destruction. Robinson C, Kirkham J, Shore R, editors. Boca Raton: CRC Press, pp. 59–84.
24.
Steinlechner M, Berger B, Niederstatter H, Parson W -2002-. Rare failures in the amelogenin sex test. Int J Legal Med116:117–120.
25.
Steiper ME, Ruvolo M -2003-. Genetic sex identification in orangutans. Anthropol Anz61:1–5.
26.
Sullivan KM, Mannucci A, Kimpton CP, Gill P -1993-. A rapid and quantitative DNA sex test: fluorescence-based pcr analysis of X-Y homologous gene amelogenin. BioTechniques15:636–642.
27.
Thompson J, Higgins D, Gibson T -1994-. CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, positions-specific gap penalties and weight matrix choice. Nucleic Acids Res22:4673–4680.
28.
Toyosawa S, O’hUigin C, Figueroa F, Tichy H, Klein J -1998-. Identification and characterization of amelogenin genes in monotremes, reptiles and amphibians. Proc Natl Acad Sci USA95:13056–13061.
29.
Watson JM, Spencer JA, Graves JAM, Snead ML, Lau EC -1992-. Autosomal localization of the amelogenin gene in monotremes and marsupials: implications for mammalian sex chromosome evolution. Genomics14:785–789.
30.
Yamamoto K, Tsubota T, Komatsu T, Katayama A, Murase T, Kita I, et al. -2002-. Sex identification of Japanese black bear, Ursus thibetanus japonicus, by PCR based on amelogenin gene. J Vet Med Sci64:505–508.
