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Vol. 50 No. 4, 2011
The
Process of Cornification in the Horny Teeth of the Lamprey Involves
Proteins in the Keratin Range and Other Keratin-Associated Proteins
Lorenzo Alibardi1,* and Anna Segalla2
1Dipartimento di Biologia evoluzionistica sperimentale, Univ. of Bologna, Bologna 40126, Italy
2Dipartimento di Biologia, Univ. of Padova, Padova, 35100, Italy
Lorenzo Alibardi and Anna Segalla (2011) A
microscopic and electrophoretic study was conducted on the horny teeth
of the lamprey to increase our knowledge of the process of
cornification. Electron-dense bundles of keratin but no
keratohyaline-like granules accumulated in the cytoplasm of
transitional cells that were incorporated in the dense stratum corneum
of the tooth. Mature corneocytes were delimited by a cell corneous
envelope and formed corneous microridges on the tooth surface. Although
the increase in the electron density of the corneous layer suggested
the presence of sulfur, the low to absent reaction for sulfhydryl
groups indicated that cysteine was largely oxidized to form disulphide
bonds in the corneous material of the teeth. A 2-dimensional
electrophoretic analysis of the corneous material from the horny teeth
showed the presence of acidic proteins, most likely keratins of 45-66
kDa. Keratin 10 immunoreactivity was present in the teeth. Based on the
size, it is likely that acidic and basic non-keratin proteins of 16-20
kDa were also present in the oral mucosa, generally in higher amounts
than keratins. This suggests that the low-molecular-weight basic
proteins are likely associated with acidic keratins to produce the
dense corneous material of the tooth, a process that also occurs in
hard skin derivatives of other vertebrates.
Key words: Lamprey, Horny teeth, Cornification, Keratins, Keratin-associated proteins.
*Correspondence: Tel: 39-051-2094257. Fax: 39-051-2094286. E-mail:lorenzo.alibardi@unibo.it
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