Alternative Splicing of Amelogenin mRNA from Rat Incisor Ameloblasts

Li, R.; Li, W.; DenBesten, Pamela

doi:10.1177/00220345950740121101

Cited by 39 publications

(42 citation statements)

References 17 publications

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“…In rat, the amelogenin mRNAs that have been identified, with the exception of the exon 7 types, are R195 (contains exons 2, 3, 4, 5, 6ABCD, and 7), R181 (exons 2, 3, 5, 6ABCD, and 7), R73 (exons 2, 3, 4, 5, 6D, and 7), R59 (exons 2, 3, 5, 6D, and 7) (13), and R2-156 (exons 2, 3, 5 6BCD, and 7) (10). In addition, the amelogenin mRNAs that contain exon 8 are R1-203 (contains exons 2, 3, 5, 6ABCD, and 8), R1-179 (exons 2, 3, 5, 6BCD, and 8), R1-82 (abc) (exons 2, 3, 5, 6D, and 8), and R1-57 (exons 2, 3, 5, and 8) (10). The smaller splice products with deletion of exon 6ABC are known as LRAP and have been shown to act differently as signaling molecules affecting ameloblasts and other cell types (12)(13)(14)(15).…”

Section: Discussionmentioning

confidence: 99%

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The Exon 6ABC Region of Amelogenin mRNA Contribute to Increased Levels of Amelogenin mRNA through Amelogenin Protein-enhanced mRNA Stabilization

Harada

Taniguchi

2006

Journal of Biological Chemistry

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We recently demonstrated that the reuptake of full-length amelogenin protein results in increased levels of amelogenin mRNA through enhanced mRNA stabilization (Xu, L., Harada, H., Tamaki, T. Y., Matsumoto, S., Tanaka, J., and Taniguchi, A. (2006) J. Biol. Chem. 281, 2257-2262). Here, we examined the molecular mechanism of enhanced amelogenin mRNA stabilization. To identify the cis-regulatory region within amelogenin mRNA, we tested various reporter systems using a deletion series of reporter plasmids. A deletion at exon 6ABC of amelogenin mRNA resulted in a 2.5-fold increase in the amelogenin mRNA expression level when compared with that of full-length mRNA, indicating that a cis-element exists in exon 6ABC of amelogenin mRNA. Furthermore, Northwestern analysis demonstrated that amelogenin protein binds directly to its mRNA in vitro, suggesting that amelogenin protein acts as a trans-acting protein that specifically binds to this cis-element. Moreover, recombinant mouse amelogenin protein extended the half-life of full-length amelogenin mRNA but did not significantly alter the half-life of exon 6ABC-deletion mutant mRNA. The splice products produced by deletion of exon 6ABC are known as leucine-rich amelogenin peptides and have signaling effects on cells. Our findings also suggest that the regulation of full-length amelogenin protein expression differs from the regulation of leucine-rich amelogenin peptide expression.Amelogenin is a major component of enamel matrix. Amelogenin is unique in its localization on both X-chromosomes and Y-chromosomes in cows, pigs, and humans and on the X-chromosomes in mice (1-4) rather than on chromosome 4q like other enamel-and mineralization-associated proteins. Alternative splicing of amelogenin pre-mRNA leads to the production of many isoforms (5-11). The smaller splice products, produced upon the deletion of exon 6ABC, are known as the leucine-rich amelogenin peptides or LRAPs.2 Both full-length amelogenin and LRAP are capable of modulating expression of cementoblast-associated genes (12-16). In particular, LRAPs have been shown to act differently, as signaling molecules affecting odontogenic and other cell types (12-15). The larger forms, those that contain the intact proline-rich, hydrophobic exon 6 domains, are important for enamel mineralization (for review, see Ref. 17). Thus, the mRNA products of short and full-length amelogenin have different functions, and the regulation of full-length amelogenin protein expression appears to differ from the regulation of LRAP expression. CCAAT/enhancer-binding protein ␣ plays a key role in the developmentally regulated expression of the amelogenin gene at the transcription level (18), whereas Msx2 mediates interference with the binding of CCAAT/enhancer-binding protein ␣ to its cognate site on the mouse amelogenin minimal promoter by protein-protein interaction (19). Our previous study indicated that the reuptake of full-length amelogenin protein results in increased levels of amelogenin mRNA through enhanced mRNA stabilization (20)....

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Section: Discussionmentioning

confidence: 99%

“…1A). In the case of rat amelogenin cDNA, R1 isoforms, which have a deletion exon 7 and encode exon 8, are major transcripts (10). Thus, we used R1 from amelogenin cDNA in this study.…”

Section: Presence Of a Cis-acting Element In Exon 6abcmentioning

confidence: 99%

The Exon 6ABC Region of Amelogenin mRNA Contribute to Increased Levels of Amelogenin mRNA through Amelogenin Protein-enhanced mRNA Stabilization

Harada

Taniguchi

2006

Journal of Biological Chemistry

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“…This phenomenon is known in bovine (Gibson et al 1991), human (Salido et al 1992), pig (Yamakoshi et al 1994), rodents Bonass et al 1994;Li et al 1995), and opossum (Hu et al 1996a). Therefore, it could also exist in the other species studied.…”

Section: Sequence Conservation and Alternative Rna Splicingmentioning

confidence: 91%

Molecular Evolution of Amelogenin in Mammals

2005

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Abstract. An evolutionary analysis of mammalian amelogenin, the major protein of forming enamel, was conducted by comparison of 26 sequences (including 14 new ones) representative of the main mammalian lineages. Amelogenin shows highly conserved residues in the hydrophilic N-and C-terminal regions. The central hydrophobic region (most of exon 6) is more variable, but it has conserved a high amount of proline and glutamine located in triplets, PXQ, indicating that these residues play an important role. This region evolves more rapidly, and is less constrained, than the other well-conserved regions, which are subjected to strong constraints. The comparison of the substitution rates in relation to the CpG richness confirmed that the highly conserved regions are subjected to strong selective pressures. The amino acids located at important sites and the residues known to lead to amelogenesis imperfecta when substituted were present in all sequences examined. Evolutionary analysis of the variable region of exon 6 points to a particular zone, rich in either amino acid insertion or deletion. We consider this region a hot spot of mutation for the mammalian amelogenin. In this region, numerous triplet repeats (PXQ) have been inserted recently and independently in five lineages, while most of the hydrophobic exon 6 region probably had its origin in several rounds of triplet insertions, early in vertebrate evolution. The putative ancestral DNA sequence of the mammalian amelogenin was calculated using a maximum likelihood approach. The putative ancestral protein was composed of 177 residues. It already contained all important amino acid positions known to date, its hydrophobic variable region was rich in proline and glutamine, and it contained triplet repeats PXQ as in the modern sequences.

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“…In addition, alternative splicing has also been identified as a mechanism for generation of heterogeneous amelogenin products; all proteins derived from alternatively spliced transcripts have homologous 5' and 3' sequences within the coding regions (Gibson et al, 1992;Lau et al, 1992;Salido et al, 1992;Simmer et al, 1994;Li et al, 1995). The canine AMEL gene has been found to be located on both X and Y chromosomes (Yan et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Identification of cDNA sequences and alternative splicing patterns of canine AMEL genes (AMELX and AMELY)

Yan

Bai

et al. 2015

Genet. Mol. Res.

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ABSTRACT. Amelogenin is a major protein of the developing enamel matrix. There are two amelogenin genes (AMELX and AMELY) located on the X and Y chromosomes, respectively, in dogs. In the present study, we characterized full-length cDNAs and alternative splicing patterns of the AMEL genes in the tooth tissue of a dog by 5'-and 3'-rapid amplification of cDNA ends and AMEL-specific RT-PCR. Sequence analysis revealed that the coding regions of AMELX and AMELY were 579 and 576 bp (accession Nos. KP244310 and KP244311), respectively. The coding sequence of AMELX had 95.1% identity to that of AMELY. The AMEL genes on X and Y chromosomes were both expressed in developing tooth tissue. Eight different alternatively spliced transcripts were identified, five from AMELX and three from AMELY.

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Alternative Splicing of Amelogenin mRNA from Rat Incisor Ameloblasts

Cited by 39 publications

References 17 publications

The Exon 6ABC Region of Amelogenin mRNA Contribute to Increased Levels of Amelogenin mRNA through Amelogenin Protein-enhanced mRNA Stabilization

The Exon 6ABC Region of Amelogenin mRNA Contribute to Increased Levels of Amelogenin mRNA through Amelogenin Protein-enhanced mRNA Stabilization

Molecular Evolution of Amelogenin in Mammals

Identification of cDNA sequences and alternative splicing patterns of canine AMEL genes (AMELX and AMELY)

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