Chapter 7
Retinoic Acid Signaling
and the Zebrafish Dentition During
Development and Evolution
William R. Jackman and Yann Gibert
Abstract Explaining how the extensive diversity in form of vertebrate teeth arose
in evolution and the mechanisms by which teeth are made during embryogenesis
are intertwined questions that can merit from a better understanding of the roles of
retinoic acid (RA) in tooth development. Pioneering studies in rodents showed that
dietary vitamin A (VA), and eventually RA (one of the major active metabolites of
VA), are required for proper tooth formation and that dentin-forming odontoblast cells
seem to be especially sensitive to changes in RA levels. Later, rodent studies further
indicated that RA signaling interactions with other cell-signaling pathways are an
important part of RA’s actions in odontogenesis. Recent investigations employing
zebrafish and other teleost fish continued this work in an evolutionary context, and
specifically demonstrated that RA is required for the initiation of tooth development.
RA is also sufficient in certain circumstances to induce de novo tooth formation. Both
effects appear to involve cranial-neural crest cells, again suggesting that RA signaling
has a particular influence on odontoblast development. These teleost studies have
also highlighted both evolutionary conservation and change in how RA is employed
during odontogenesis in different vertebrate lineages, and thus raises the possibility
that developmental changes to RA signaling has led to some of the diversity of form
seen across vertebrate dentitions. Future progress in this area will come at least in
part from expanding the species examined to get a better picture of how often RA
signaling has changed in evolution and how this relates to the evolution of dental
form.
Keywords Vitamin A · Retinoic Acid · Signaling · Vitamin A deficiency ·
Evolution · Development · Tooth · Odontoblast · Teleost · Zebrafish · Rodents ·
Dentition · Ameloblast · Dentin · Enamel
W. R. Jackman (B)
Bowdoin College, 6500 College Station, Brunswick, ME 04011, USA
e-mail: wjackman@bowdoin.edu
Y. Gibert
University of Mississippi Medical Center, Jackson, MS 39216, USA
e-mail: ygibert@umc.edu
© Springer Nature Switzerland AG 2020
M. A. Asson-Batres and C. Rochette-Egly (eds.), The Biochemistry of Retinoid
Signaling III, Subcellular Biochemistry 95,
https://doi.org/10.1007/978-3-030-42282-0_7
175
Retinoic Acid Signaling
and the Zebrafish Dentition During
Development and Evolution
William R. Jackman and Yann Gibert
Abstract Explaining how the extensive diversity in form of vertebrate teeth arose
in evolution and the mechanisms by which teeth are made during embryogenesis
are intertwined questions that can merit from a better understanding of the roles of
retinoic acid (RA) in tooth development. Pioneering studies in rodents showed that
dietary vitamin A (VA), and eventually RA (one of the major active metabolites of
VA), are required for proper tooth formation and that dentin-forming odontoblast cells
seem to be especially sensitive to changes in RA levels. Later, rodent studies further
indicated that RA signaling interactions with other cell-signaling pathways are an
important part of RA’s actions in odontogenesis. Recent investigations employing
zebrafish and other teleost fish continued this work in an evolutionary context, and
specifically demonstrated that RA is required for the initiation of tooth development.
RA is also sufficient in certain circumstances to induce de novo tooth formation. Both
effects appear to involve cranial-neural crest cells, again suggesting that RA signaling
has a particular influence on odontoblast development. These teleost studies have
also highlighted both evolutionary conservation and change in how RA is employed
during odontogenesis in different vertebrate lineages, and thus raises the possibility
that developmental changes to RA signaling has led to some of the diversity of form
seen across vertebrate dentitions. Future progress in this area will come at least in
part from expanding the species examined to get a better picture of how often RA
signaling has changed in evolution and how this relates to the evolution of dental
form.
Keywords Vitamin A · Retinoic Acid · Signaling · Vitamin A deficiency ·
Evolution · Development · Tooth · Odontoblast · Teleost · Zebrafish · Rodents ·
Dentition · Ameloblast · Dentin · Enamel
W. R. Jackman (B)
Bowdoin College, 6500 College Station, Brunswick, ME 04011, USA
e-mail: wjackman@bowdoin.edu
Y. Gibert
University of Mississippi Medical Center, Jackson, MS 39216, USA
e-mail: ygibert@umc.edu
© Springer Nature Switzerland AG 2020
M. A. Asson-Batres and C. Rochette-Egly (eds.), The Biochemistry of Retinoid
Signaling III, Subcellular Biochemistry 95,
https://doi.org/10.1007/978-3-030-42282-0_7
175