Melanocortin Receptor 1 (MC1R) Mutations and Coat Color in Pigs

Abstract The melanocortin receptor 1 (MC1R) plays a central role in regulation of eumelanin (black/brown) and phaeomelanin (red/yellow) synthesis within the mammalian melanocyte and is encoded by the classical Extension (E) coat color locus. Sequence analysis of MC1R from seven porcine breeds revealed a total of four allelic variants corresponding to five different E alleles. The European wild boar possessed a unique MC1R allele that we believe is required for the expression of a wild-type coat color. Two different MC1R alleles were associated with the dominant black color in pigs. MC1R*2 was found in European Large Black and Chinese Meishan pigs and exhibited two missense mutations compared with the wild-type sequence. Comparative data strongly suggest that one of these, L99P, may form a constitutively active receptor. MC1R*3 was associated with the black color in the Hampshire breed and involved a single missense mutation D121N. This same MC1R variant was also associated with EP, which results in black spots on a white or red background. Two different missense mutations were identified in recessive red (e/e) animals. One of these, A240T, occurs at a highly conserved position, making it a strong candidate for disruption of receptor function.

Download Full-text

Comprehensive genetic testing combined with citizen science reveals a recently characterized ancient MC1R mutation is associated with partial recessive red phenotypes in dog

10.21203/rs.3.rs-36023/v1 ◽

2020 ◽

Author(s):

Heidi Anderson ◽

Leena Honkanen ◽

Päivi Ruotanen ◽

Julia Mathlin ◽

Jonas Donner

Keyword(s):

Citizen Science ◽

Coat Color ◽

Allelic Variation ◽

Wild Type ◽

Melanocortin 1 Receptor ◽

Phenotype Analysis ◽

Genotype Screening ◽

Dominant Black ◽

Novel Allele

Abstract Background The Melanocortin 1 Receptor (MC1R) plays a central role in regulation of coat color determination in dogs and is commonly referred to as the “E (extension) Locus”. Allelic variation of the MC1R gene is associated with coat color phenotypes EM (melanistic mask), EG (grizzle/domino) and e1–3 (recessive red) in dogs. In addition, a previous study of archeological dog specimens over 10,000 years of age identified a variant p.R301C in the MC1R gene that may have influenced coat color of early dogs. Results Commercial genotyping of 11,726 dog samples showed the R301C variant of the MC1R gene was present in 34 breeds or breed varieties, at an allele frequency of 1.48% in the tested population. We detected no linkage disequilibrium between R301C and other tested alleles of the E locus. Based on current convention we propose that R301C should be considered a novel allele of the E locus, which we have termed eA for “e ancient”. Phenotype analysis of owner-provided dog pictures reveals eA allele has an impact on coat color and is recessive to wild type E and dominant to the e alleles. In dominant black (KB/*) dogs it can prevent the expression of the K locus, and the expressed coat color is solely determined by the A locus. In the absence of dominant black, eA/eA and eA/e genotypes result in the coat color patterns referred to in their respective breed communities as domino in Alaskan Malamute and other Spitz breeds, grizzle in Chihuahua, and pied in Beagle. Conclusions This study demonstrates a large genotype screening effort to identify the frequency and distribution of the MC1R R301C variant, one of the earliest mutations captured by canine domestication, and citizen science empowered characterization of its impact on coat color.

Download Full-text

Comprehensive genetic testing combined with citizen science reveals a recently characterized ancient MC1R mutation associated with partial recessive red phenotypes in dog

Canine Medicine and Genetics ◽

10.1186/s40575-020-00095-7 ◽

2020 ◽

Vol 7 (1) ◽

Author(s):

Heidi Anderson ◽

Leena Honkanen ◽

Päivi Ruotanen ◽

Julia Mathlin ◽

Jonas Donner

Keyword(s):

Citizen Science ◽

Coat Color ◽

Allelic Variation ◽

Phenotypic Expression ◽

Wild Type ◽

Melanocortin 1 Receptor ◽

Phenotype Analysis ◽

Genotype Screening ◽

Dominant Black

Abstract Background The Melanocortin 1 Receptor (MC1R) plays a central role in regulation of coat color determination in various species and is commonly referred to as the “E (extension) Locus”. Allelic variation of the MC1R gene is associated with coat color phenotypes EM (melanistic mask), EG (grizzle/domino) and e1–3 (recessive red) in dogs. In addition, a previous study of archeological dog specimens over 10,000 years of age identified a variant p.R301C in the MC1R gene that may have influenced coat color of early dogs. Results Commercial genotyping of 11,750 dog samples showed the R301C variant of the MC1R gene was present in 35 breeds or breed varieties, at an allele frequency of 1.5% in the tested population. We detected no linkage disequilibrium between R301C and other tested alleles of the E locus. Based on current convention we propose that R301C should be considered a novel allele of the E locus, which we have termed eA for “e ancient red”. Phenotype analysis of owner-provided dog pictures reveals that the eA allele has an impact on coat color and is recessive to wild type E and dominant to the e alleles. In dominant black (KB/*) dogs it can prevent the phenotypic expression of the K locus, and the expressed coat color is solely determined by the A locus. In the absence of dominant black, eA/eA and eA/e genotypes result in the coat color patterns referred to in their respective breed communities as domino in Alaskan Malamute and other Spitz breeds, grizzle in Chihuahua, and pied in Beagle. Conclusions This study demonstrates a large genotype screening effort to identify the frequency and distribution of the MC1R R301C variant, one of the earliest mutations captured by canine domestication, and citizen science empowered characterization of its impact on coat color.

Download Full-text

Comprehensive genetic testing combined with citizen science reveals a recently characterized ancient MC1R mutation is associated with partial recessive red phenotypes in dog

10.21203/rs.3.rs-36023/v2 ◽

2020 ◽

Author(s):

Heidi Anderson ◽

Leena Honkanen ◽

Päivi Ruotanen ◽

Julia Mathlin ◽

Jonas Donner

Keyword(s):

Citizen Science ◽

Coat Color ◽

Allelic Variation ◽

Wild Type ◽

Melanocortin 1 Receptor ◽

Phenotype Analysis ◽

Genotype Screening ◽

Dominant Black ◽

Novel Allele

Abstract Background: The Melanocortin 1 Receptor (MC1R) plays a central role in regulation of coat color determination in dogs and is commonly referred to as the “E (extension) Locus”. Allelic variation of the MC1R gene is associated with coat color phenotypes EM (melanistic mask), EG (grizzle/domino) and e1-3 (recessive red) in dogs. In addition, a previous study of archeological dog specimens over 10,000 years of age identified a variant p.R301C in the MC1R gene that may have influenced coat color of early dogs.Results: Commercial genotyping of 11,750 dog samples showed the R301C variant of the MC1R gene was present in 35 breeds or breed varieties, at an allele frequency of 1.5% in the tested population. We detected no linkage disequilibrium between R301C and other tested alleles of the E locus. Based on current convention we propose that R301C should be considered a novel allele of the E locus, which we have termed eA for “e ancient red”. Phenotype analysis of owner-provided dog pictures reveals that the eA allele has an impact on coat color and is recessive to wild type E and dominant to the e alleles. In dominant black (KB/*) dogs it can prevent the expression of the K locus, and the expressed coat color is solely determined by the A locus. In the absence of dominant black, eA/eA and eA/e genotypes result in the coat color patterns referred to in their respective breed communities as domino in Alaskan Malamute and other Spitz breeds, grizzle in Chihuahua, and pied in Beagle.Conclusions: This study demonstrates a large genotype screening effort to identify the frequency and distribution of the MC1R R301C variant, one of the earliest mutations captured by canine domestication, and citizen science empowered characterization of its impact on coat color.

Download Full-text

Comprehensive genetic testing combined with citizen science reveals a recently characterized ancient MC1R mutation associated with partial recessive red phenotypes in dog

10.21203/rs.3.rs-36023/v3 ◽

2020 ◽

Author(s):

Heidi Anderson ◽

Leena Honkanen ◽

Päivi Ruotanen ◽

Julia Mathlin ◽

Jonas Donner

Keyword(s):

Citizen Science ◽

Coat Color ◽

Allelic Variation ◽

Phenotypic Expression ◽

Wild Type ◽

Melanocortin 1 Receptor ◽

Phenotype Analysis ◽

Genotype Screening ◽

Dominant Black

Abstract Background: The Melanocortin 1 Receptor (MC1R) plays a central role in regulation of coat color determination in various species and is commonly referred to as the “E (extension) Locus”. Allelic variation of the MC1R gene is associated with coat color phenotypes EM (melanistic mask), EG (grizzle/domino) and e1-3 (recessive red) in dogs. In addition, a previous study of archeological dog specimens over 10,000 years of age identified a variant p.R301C in the MC1R gene that may have influenced coat color of early dogs.Results: Commercial genotyping of 11,750 dog samples showed the R301C variant of the MC1R gene was present in 35 breeds or breed varieties, at an allele frequency of 1.5% in the tested population. We detected no linkage disequilibrium between R301C and other tested alleles of the E locus. Based on current convention we propose that R301C should be considered a novel allele of the E locus, which we have termed eA for “e ancient red”. Phenotype analysis of owner-provided dog pictures reveals that the eA allele has an impact on coat color and is recessive to wild type E and dominant to the e alleles. In dominant black (KB/*) dogs it can prevent the phenotypic expression of the K locus, and the expressed coat color is solely determined by the A locus. In the absence of dominant black, eA/eA and eA/e genotypes result in the coat color patterns referred to in their respective breed communities as domino in Alaskan Malamute and other Spitz breeds, grizzle in Chihuahua, and pied in Beagle.Conclusions: This study demonstrates a large genotype screening effort to identify the frequency and distribution of the MC1R R301C variant, one of the earliest mutations captured by canine domestication, and citizen science empowered characterization of its impact on coat color.

Download Full-text

Platelet Activation and Aggregation Induced by Recombinant von Willebrand Factors Reproducing Four Type 2B von Willebrand Disease Missense Mutations

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614241 ◽

1998 ◽

Vol 79 (01) ◽

pp. 211-216 ◽

Cited By ~ 13

Author(s):

Lysiane Hilbert ◽

Claudine Mazurier ◽

Christophe de Romeuf

Keyword(s):

Platelet Aggregation ◽

Platelet Activation ◽

Von Willebrand Disease ◽

Platelet Glycoprotein ◽

Missense Mutations ◽

Inhibit Platelet Aggregation ◽

Wild Type ◽

A1 Domain ◽

Von Willebrand ◽

Willebrand Factor

SummaryType 2B of von Willebrand disease (vWD) refers to qualitative variants with increased affinity of von Willebrand factor (vWF) for platelet glycoprotein Ib (GPIb). All the mutations responsible for type 2B vWD have been located in the A1 domain of vWF. In this study, various recombinant von Willebrand factors (rvWF) reproducing four type 2B vWD missense mutations were compared to wild-type rvWF (WT-rvWF) for their spontaneous binding to platelets and their capacity to induce platelet activation and aggregation. Our data show that the multimeric pattern of each mutated rvWF is similar to that of WT-rvWF but the extent of spontaneous binding and the capacity to induce platelet activation and aggregation are more important for the R543Q and V553M mutations than for the L697V and A698V mutations. Both the binding of mutated rvWFs to platelets and platelet aggregation induced by type 2B rvWFs are inhibited by monoclonal anti-GPIb and anti-vWF antibodies, inhibitors of vWF binding to platelets in the presence of ristocetin, as well as by aurin tricarboxylic acid. On the other hand, EDTA and a monoclonal antibody directed against GPIIb/IIIa only inhibit platelet aggregation. Furthermore, the incubation of type 2B rvWFs with platelets, under stirring conditions, results in the decrease in high molecular weight vWF multimers in solution, the extent of which appears correlated with that of plasma vWF from type 2B vWD patients harboring the corresponding missense mutation. This study supports that the binding of different mutated type 2B vWFs onto platelet GPIb induces various degrees of platelet activation and aggregation and thus suggests that the phenotypic heterogeneity of type 2B vWD may be related to the nature and/or location of the causative point mutation.

Download Full-text

Structural and Thermodynamic Analysis of the Resistance Development to Pimodivir (VX-787), the Clinical Inhibitor of Cap Binding to PB2 Subunit of Influenza A Polymerase

Molecules ◽

10.3390/molecules26041007 ◽

2021 ◽

Vol 26 (4) ◽

pp. 1007

Author(s):

Jiří Gregor ◽

Kateřina Radilová ◽

Jiří Brynda ◽

Jindřich Fanfrlík ◽

Jan Konvalinka ◽

...

Keyword(s):

Thermodynamic Analysis ◽

Influenza A ◽

Polymerase Activity ◽

Second Phase ◽

Missense Mutations ◽

Wild Type ◽

Resistance Development ◽

Third Phase ◽

Major Mutation ◽

Control And Prevention

Influenza A virus (IAV) encodes a polymerase composed of three subunits: PA, with endonuclease activity, PB1 with polymerase activity and PB2 with host RNA five-prime cap binding site. Their cooperation and stepwise activation include a process called cap-snatching, which is a crucial step in the IAV life cycle. Reproduction of IAV can be blocked by disrupting the interaction between the PB2 domain and the five-prime cap. An inhibitor of this interaction called pimodivir (VX-787) recently entered the third phase of clinical trial; however, several mutations in PB2 that cause resistance to pimodivir were observed. First major mutation, F404Y, causing resistance was identified during preclinical testing, next the mutation M431I was identified in patients during the second phase of clinical trials. The mutation H357N was identified during testing of IAV strains at Centers for Disease Control and Prevention. We set out to provide a structural and thermodynamic analysis of the interactions between cap-binding domain of PB2 wild-type and PB2 variants bearing these mutations and pimodivir. Here we present four crystal structures of PB2-WT, PB2-F404Y, PB2-M431I and PB2-H357N in complex with pimodivir. We have thermodynamically analysed all PB2 variants and proposed the effect of these mutations on thermodynamic parameters of these interactions and pimodivir resistance development. These data will contribute to understanding the effect of these missense mutations to the resistance development and help to design next generation inhibitors.

Download Full-text

High Polymorphism at the Human Melanocortin 1 Receptor Locus

Genetics ◽

10.1093/genetics/151.4.1547 ◽

1999 ◽

Vol 151 (4) ◽

pp. 1547-1557 ◽

Cited By ~ 4

Author(s):

Brinda K Rana ◽

David Hewett-Emmett ◽

Li Jin ◽

Benny H-J Chang ◽

Naymkhishing Sambuughin ◽

...

Keyword(s):

Protein Sequence ◽

Nucleotide Diversity ◽

Coat Color ◽

Low Frequency ◽

Melanocortin Receptor ◽

Human Populations ◽

Melanocortin 1 Receptor ◽

Mc1r Gene ◽

Southeast Asians ◽

Color Changes

Abstract Variation in human skin/hair pigmentation is due to varied amounts of eumelanin (brown/black melanins) and phaeomelanin (red/yellow melanins) produced by the melanocytes. The melanocortin 1 receptor (MC1R) is a regulator of eu- and phaeomelanin production in the melanocytes, and MC1R mutations causing coat color changes are known in many mammals. We have sequenced the MC1R gene in 121 individuals sampled from world populations with an emphasis on Asian populations. We found variation at five nonsynonymous sites (resulting in the variants Arg67Gln, Asp84Glu, Val92Met, Arg151Cys, and Arg163Gln), but at only one synonymous site (A942G). Interestingly, the human consensus protein sequence is observed in all 25 African individuals studied, but at lower frequencies in the other populations examined, especially in East and Southeast Asians. The Arg163Gln variant is absent in the Africans studied, almost absent in Europeans, and at a low frequency (7%) in Indians, but is at an exceptionally high frequency (70%) in East and Southeast Asians. The MC1R gene in common and pygmy chimpanzees, gorilla, orangutan, and baboon was sequenced to study the evolution of MC1R. The ancestral human MC1R sequence is identical to the human consensus protein sequence, while MC1R varies considerably among higher primates. A comparison of the rates of substitution in genes in the melanocortin receptor family indicates that MC1R has evolved the fastest. In addition, the nucleotide diversity at the MC1R locus is shown to be several times higher than the average nucleotide diversity in human populations, possibly due to diversifying selection.

Download Full-text

Investigation of the Stability of Yeast rad52 Mutant Proteins Uncovers Post-translational and Transcriptional Regulation of Rad52p

Genetics ◽

10.1093/genetics/163.1.91 ◽

2003 ◽

Vol 163 (1) ◽

pp. 91-101 ◽

Cited By ~ 1

Author(s):

Erin N Asleson ◽

Dennis M Livingston

Keyword(s):

Half Life ◽

Translational Regulation ◽

Cellular Level ◽

Missense Mutations ◽

Wild Type ◽

Mutant Proteins ◽

Gal1 Promoter ◽

Rad52 Protein ◽

The Stability ◽

Mutant Forms

Abstract We investigated the stability of the Saccharomyces cerevisiae Rad52 protein to learn how a cell controls its quantity and longevity. We measured the cellular levels of wild-type and mutant forms of Rad52p when expressed from the RAD52 promoter and the half-lives of the various forms of Rad52p when expressed from the GAL1 promoter. The wild-type protein has a half-life of 15 min. rad52 mutations variably affect the cellular levels of the protein products, and these levels correlate with the measured half-lives. While missense mutations in the N terminus of the protein drastically reduce the cellular levels of the mutant proteins, two mutations—one a deletion of amino acids 210-327 and the other a missense mutation of residue 235—increase the cellular level and half-life more than twofold. These results suggest that Rad52p is subject to post-translational regulation. Proteasomal mutations have no effect on Rad52p half-life but increase the amount of RAD52 message. In contrast to Rad52p, the half-life of Rad51p is >2 hr, and RAD51 expression is unaffected by proteasomal mutations. These differences between Rad52p and Rad51p suggest differential regulation of two proteins that interact in recombinational repair.

Download Full-text

Multiple Congenital Ocular Anomalies in a silver coat Missouri Fox Trotter stallion

Tierärztliche Praxis Ausgabe G Großtiere / Nutztiere ◽

10.1055/a-1581-4810 ◽

2021 ◽

Vol 49 (05) ◽

pp. 350-354

Author(s):

Verena Maria Herb ◽

Verena Zehetner ◽

Klaas-Ole Blohm

Keyword(s):

Missense Mutation ◽

Coat Color ◽

Incidental Finding ◽

Unknown Origin ◽

Allelic Frequency ◽

Cystic Lesions ◽

Wild Type Allele ◽

Wild Type ◽

Type Allele ◽

Phenotype Characterization

AbstractThis is the first description of Multiple Congenital Ocular Anomalies (MCOA) in a silver coat Missouri Fox Trotter determined to be heterozygous for the Silver PMEL17 missense mutation associated with MCOA and a silver coat in other breeds. The stallion was treated for meningoencephalitis and bilateral uveitis of unknown origin. A complete ophthalmic examination and ocular ultrasonography were performed. As an incidental finding, the patient exhibited bilateral cystic lesions restricted to the temporal anterior uvea consistent with the Cyst phenotype and was genotyped heterozygous for the Silver mutation. Additionally, 4 other non-silver colored Missouri Fox Trotters were genotyped homozygous for the wild-type allele. Screening for PMEL17 mutation in Missouri Fox Trotters accompanied by ophthalmic phenotype characterization is recommended to determine the allelic frequency and facilitate informed breeding decisions since the silver coat color is particularly popular.

Download Full-text

Abstract P459: Mavacamten And Danicamtiv Reverse Respective Contractile Abnormalities In Engineered Heart Tissue Models Of Hypertrophic And Dilated Cardiomyopathy

Circulation Research ◽

10.1161/res.129.suppl_1.p459 ◽

2021 ◽

Vol 129 (Suppl_1) ◽

Author(s):

Saiti S Halder ◽

Lorenzo R Sewanan ◽

Michael J Rynkiewicz ◽

Jeffrey R Moore ◽

William J Lehman ◽

...

Keyword(s):

Dilated Cardiomyopathy ◽

Calcium Sensitivity ◽

Heart Tissue ◽

Missense Mutations ◽

Wild Type ◽

Twitch Force ◽

In Vitro Motility ◽

Isometric Twitch ◽

Engineered Heart Tissues

Missense mutations in alpha-tropomyosin (TPM1) can lead to development of hypertrophic (HCM) or dilated cardiomyopathy (DCM). HCM mutation E62Q and DCM mutation E54K have previously been studied extensively in experimental systems ranging from in vitro biochemical assays to animal models, although some conflicting results have been found. We undertook a detailed multi-scale assessment of these mutants that included atomistic simulations, regulated in vitro motility (IVM) assays, and finally physiologically relevant human engineered heart tissues. In IVM assays, E62Q previously has shown increased Calcium sensitivity. New molecular dynamics data shows mutation-induced changes to tropomyosin dynamics and interactions with actin and troponin. Human engineered heart tissues (EHT) were generated by seeding iPSC-derived cardiomyocytes engineered using CRISPR/CAS9 to express either E62Q or E54K cardiomyopathy mutations. After two weeks in culture, E62Q EHTs showed a drastically hypercontractile twitch force and significantly increased stiffness while displaying little difference in twitch kinetics compared to wild-type isogenic control EHTs. On the other hand, E54K EHTs displayed hypocontractile isometric twitch force with faster kinetics, impaired length-dependent activation and lowered stiffness. Given these contractile abnormalities, we hypothesized that small molecule myosin modulators to appropriately activate or inhibit myosin activity would restore E54K or E62Q EHTs to normal behavior. Accordingly, E62Q EHTs were treated with 0.5μM mavacamten (to remedy hypercontractility) and E54K EHTs with 0.5 μM danicamtiv (to remedy hypocontractility) for 4 days, followed by a 1 day washout period. Upon contractility testing, it was observed that the drugs were able to reverse contractile phenotypes observed in mutant EHTs and restore contractile properties to levels resembling those of the untreated wild type group. The computational, IVM and EHT studies provide clear evidence in support of the hyper- vs. hypo-contractility paradigm as a common axis that distinguishes HCM and DCM TPM1 mutations. Myosin modulators that directly compensate for underlying myofilament aberrations show promising efficacy in human in vitro systems.

Download Full-text