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Characterizing Melanocyte Development in the Marine Annelid Capitella teleta.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Characterizing Melanocyte Development in the Marine Annelid Capitella teleta./
Author:	Tischofer, Vanessa.
Description:	1 online resource (117 pages)
Notes:	Source: Masters Abstracts International, Volume: 84-11.
Contained By:	Masters Abstracts International84-11.
Subject:	Biology. -
Online resource:	click for full text (PQDT)
ISBN:	9798379495893

Characterizing Melanocyte Development in the Marine Annelid Capitella teleta.
Tischofer, Vanessa.

Characterizing Melanocyte Development in the Marine Annelid Capitella teleta. - 1 online resource (117 pages)

Source: Masters Abstracts International, Volume: 84-11.

Thesis (M.S.)--Clark University, 2023.

Includes bibliographical references

The presence of the pigment melanin is widely distributed across different clades of organisms in both prokaryotes and eukaryotes. However, despite the widespread prevalence of melanin, the evolutionary pathway of melanin-producing cells in animals and their homology across taxa remains understudied. In vertebrates, melanin synthesis occurs in specialized cells known as melanocytes, which can produce multiple types of melanin. These cells arise from the neural crest, which is thought to be a vertebrate innovation, and are specified by a combination of BMP and Wnt signaling at differing times. Once cells become melanocytes in vertebrates, they express the transcription factor MITF, which up-regulates expression of melanin-producing enzymes such as Tyrosinase and Tyrosinase-Related protein 1 and Tyrosinase-Related protein 2 (also known as Dopachrome Tautomerase). In contrast, in insects, melanin and other related pigments are secreted into the cuticle from the epidermis. Due to these large differences, it was hypothesized that melanin-producing cells have evolved convergently across taxa. Vertebrates and insects are each part of two major animal clades in Bilateria, the deuterostomes and the ecdysozoans, respectively. Very little research on melanocyte development has been conducted on animals in the third major bilaterian clade, Spiralia, which includes annelids. To better understand melanocyte evolution, we studied the marine annelid Capitella teleta. We characterized melanocyte formation in the head (episphere) of C. teleta embryos and larvae and found that these cells first begin forming in the ectoderm just after gastrulation and appear to be largely mature and stable in number by late larval stages. We also identified homologs of the enzymes Tyrosinase and Tyrosinase-Related Protein and the transcription factor MITF in the C. teleta genome. Tyrosinase and MITF were found to be expressed in patches of ectodermal cells byin situ hybridization, but further characterization is needed to see if these genes are expressed specifically in melanocytes. We tested the function of BMP and Wnt signaling during melanogenesis in C. teleta using both protein ligands and pharmacological agents. When BMP protein was added at the 64-cell stage (prior to gastrulation), there was an increase in the number of melanocytes in the resulting larvae. In contrast, upregulation of Wnt signaling strongly reduced melanocyte production, but downregulation of Wnt signaling did not appear to affect melanocyte production. As such, both BMP and Wnt signaling play a role in melanogenesis in annelids, albeit in a different regulation pattern than is seen in vertebrates or in insects. Overall, our data suggest that melanocytes in C. teleta develop differently than melanocytes in vertebrates, suggesting that they are not homologous. However, future studies examining melanocyte development across spiralian taxa will be important in understanding how melanocytes evolved in animals.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798379495893Subjects--Topical Terms:

599573
Biology.
Subjects--Index Terms:

Capitella teletaIndex Terms--Genre/Form:

554714
Electronic books.

Characterizing Melanocyte Development in the Marine Annelid Capitella teleta.
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520 $a The presence of the pigment melanin is widely distributed across different clades of organisms in both prokaryotes and eukaryotes. However, despite the widespread prevalence of melanin, the evolutionary pathway of melanin-producing cells in animals and their homology across taxa remains understudied. In vertebrates, melanin synthesis occurs in specialized cells known as melanocytes, which can produce multiple types of melanin. These cells arise from the neural crest, which is thought to be a vertebrate innovation, and are specified by a combination of BMP and Wnt signaling at differing times. Once cells become melanocytes in vertebrates, they express the transcription factor MITF, which up-regulates expression of melanin-producing enzymes such as Tyrosinase and Tyrosinase-Related protein 1 and Tyrosinase-Related protein 2 (also known as Dopachrome Tautomerase). In contrast, in insects, melanin and other related pigments are secreted into the cuticle from the epidermis. Due to these large differences, it was hypothesized that melanin-producing cells have evolved convergently across taxa. Vertebrates and insects are each part of two major animal clades in Bilateria, the deuterostomes and the ecdysozoans, respectively. Very little research on melanocyte development has been conducted on animals in the third major bilaterian clade, Spiralia, which includes annelids. To better understand melanocyte evolution, we studied the marine annelid Capitella teleta. We characterized melanocyte formation in the head (episphere) of C. teleta embryos and larvae and found that these cells first begin forming in the ectoderm just after gastrulation and appear to be largely mature and stable in number by late larval stages. We also identified homologs of the enzymes Tyrosinase and Tyrosinase-Related Protein and the transcription factor MITF in the C. teleta genome. Tyrosinase and MITF were found to be expressed in patches of ectodermal cells byin situ hybridization, but further characterization is needed to see if these genes are expressed specifically in melanocytes. We tested the function of BMP and Wnt signaling during melanogenesis in C. teleta using both protein ligands and pharmacological agents. When BMP protein was added at the 64-cell stage (prior to gastrulation), there was an increase in the number of melanocytes in the resulting larvae. In contrast, upregulation of Wnt signaling strongly reduced melanocyte production, but downregulation of Wnt signaling did not appear to affect melanocyte production. As such, both BMP and Wnt signaling play a role in melanogenesis in annelids, albeit in a different regulation pattern than is seen in vertebrates or in insects. Overall, our data suggest that melanocytes in C. teleta develop differently than melanocytes in vertebrates, suggesting that they are not homologous. However, future studies examining melanocyte development across spiralian taxa will be important in understanding how melanocytes evolved in animals.
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