Ultrastructural differences between forming eumelanin and pheomelanin as revealed by the pink-eye mutation in the fowl

Brumbaugh, J. A.

doi:10.1016/0012-1606(68)90047-x

Cited by 45 publications

(36 citation statements)

References 10 publications

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“…Force microscopy images of melanosomes generally reveal smaller substructures with lateral dimensions of a few 10s of nm. These results are additionally consistent with the view of melanogenesis proposed by Brumbaugh in the late 1960′s (Brumbaugh, 1968). In that report, Brumbaugh showed that eumelanin premelanosomes comprise zigzagging longitudinal strands with crosslinks that occur every 20 nm.…”

Section: Direct Evidence For the Casing Modelsupporting

confidence: 92%

Current challenges in understanding melanogenesis: bridging chemistry, biological control, morphology, and function

Simon

Peles

Wakamatsu

et al. 2009

Pigment Cell Melanoma Res

343

305

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Melanin is a natural pigment produced within organelles, melanosomes, located in melanocytes. Biological functions of melanosomes are often attributed to the unique chemical properties of the melanins they contain; however, the molecular structure of melanins, the mechanism by which the pigment is produced, and how the pigment is organized within the melanosome remains to be fully understood. In this review, we examine the current understanding of the initial chemical steps in the melanogenesis. Most natural melanins are mixtures of eumelanin and pheomelanin, and so after presenting the current understanding of the individual pigments, we focus on the mixed melanin systems, with a critical eye towards understanding how studies on individual melanin do and do not provide insight in the molecular aspects of their structures. We conclude the review with a discussion of important issues that must be addressed in future research efforts to more fully understand the relationship between molecular and functional properties of this important class of natural pigments.

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Section: Direct Evidence For the Casing Modelsupporting

confidence: 92%

Current challenges in understanding melanogenesis: bridging chemistry, biological control, morphology, and function

Simon

Peles

Wakamatsu

et al. 2009

Pigment Cell Melanoma Res

343

305

View full text Add to dashboard Cite

show abstract

“…As in the mammalian hair, feather melanin is usually bound to the keratins forming the protein matrix of the hair and feather, respectively. In most cases, feather melanins are a mixture of eu-and pheomelanin, but the brightness and hue of the feather color does not anticipate the ratio [72]. Eumelanin and pheomelanin concentrations used to be significantly positively correlated in the feathers of females but not males [73], although the eumelanin-based coloration can be a sexually selected signal of resistance to the environmental oxidative stress [74] and other stressful events [75].…”

Section: Animal Melaninsmentioning

confidence: 99%

Melanins: Skin Pigments and Much More—Types, Structural Models, Biological Functions, and Formation Routes

Solano

2014

New Journal of Science

430

462

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This review presents a general view of all types of melanin in all types of organisms. Melanin is frequently considered just an animal cutaneous pigment and is treated separately from similar fungal or bacterial pigments. Similarities concerning the phenol precursors and common patterns in the formation routes are discussed. All melanins are formed in a first enzymatically-controlled phase, generally a phenolase, and a second phase characterized by an uncontrolled polymerization of the oxidized intermediates. In that second phase, quinones derived from phenol oxidation play a crucial role. Concerning functions, all melanins show a common feature, a protective role, but they are not merely photoprotective pigments against UV sunlight. In pathogenic microorganisms, melanization becomes a virulence factor since melanin protects microbial cells from defense mechanisms in the infected host. In turn, some melanins are formed in tissues where sunlight radiation is not a potential threat. Then, their redox, metal chelating, or free radical scavenging properties are more important than light absorption capacity. These pigments sometimes behave as a doubleedged sword, and inhibition of melanogenesis is desirable in different cells. Melanin biochemistry is an active field of research from dermatological, biomedical, cosmetical, and microbiological points of view, as well as fruit technology.

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“…Simplified, high tyrosinase activity is associated with synthesis of eumelanin whereas low activity results in the production of pheomelanin. The spherical pheomelanin premelanosomes are less organized than the rod-shaped eumelanin premelanosomes and contain less melanin (Brumbaugh 1968).…”

mentioning

confidence: 94%

Mutations in SLC45A2 Cause Plumage Color Variation in Chicken and Japanese Quail

et al. 2007

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S *S (Silver), S *N (wild type/gold), and S *AL (sex-linked imperfect albinism) form a series of alleles at the S (Silver) locus on chicken (Gallus gallus) chromosome Z. Similarly, sex-linked imperfect albinism (AL*A) is the bottom recessive allele at the orthologous AL locus in Japanese quail (Coturnix japonica). The solute carrier family 45, member 2, protein (SLC45A2), previously denoted membrane-associated transporter protein (MATP), has an important role in vesicle sorting in the melanocytes. Here we report five SLC45A2 mutations. The 106delT mutation in the chicken S *AL allele results in a frameshift and a premature stop codon and the corresponding mRNA appears to be degraded by nonsense-mediated mRNA decay. A splice-site mutation in the Japanese quail AL*A allele causes in-frame skipping of exon 4. Two independent missense mutations (Tyr277Cys and Leu347Met) were associated with the Silver allele in chicken. The functional significance of the former mutation, associated only with Silver in White Leghorn, is unclear. Ala72Asp was associated with the cinnamon allele (AL*C ) in the Japanese quail. The most interesting feature concerning the SLC45A2 variants documented in this study is the specific inhibition of expression of red pheomelanin in Silver chickens. This phenotypic effect cannot be explained on the basis of the current, incomplete, understanding of SLC45A2 function. It is an enigma why recessive null mutations at this locus cause an almost complete absence of both eumelanin and pheomelanin whereas some missense mutations are dominant and cause a specific inhibition of pheomelanin production.

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Ultrastructural differences between forming eumelanin and pheomelanin as revealed by the pink-eye mutation in the fowl

Cited by 45 publications

References 10 publications

Current challenges in understanding melanogenesis: bridging chemistry, biological control, morphology, and function

Current challenges in understanding melanogenesis: bridging chemistry, biological control, morphology, and function

Melanins: Skin Pigments and Much More—Types, Structural Models, Biological Functions, and Formation Routes

Mutations in SLC45A2 Cause Plumage Color Variation in Chicken and Japanese Quail

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