Characterization of MITF coding region in llamas.

ANELLO M, DAVERIO S, ARBELETCHE VIDAL RIOJA L, DI ROCCO F

Salt Lake City, UTAH,USA

Conferencia; 35th International Society for Animal Genetics Conference; 2016

International Society for Animal Genetics

Characterization of MITF coding region in llamas.The llama (Lama glama) is a fiber producer species that presents a wide variety of coat colors, among which white is one of the most valued. Microphthalmia-associated transcription factor (MITF) regulates the differentiation and development of melanocytes and is responsible for pigment cell-specific transcription of the melanogenesis enzyme genes. MITF consists of at least five isoforms with first specific exons, but only MITF-M is melanocyte-specific. Mutations in this isoform have been associated with white and white spotting phenotypes in many species of mammals. Previous studies of our laboratory excluded mutations in KIT coding region as responsible for these phenotypes. The aim of the present study is to describe and characterize the complete coding region of MITF-M and to detect mutations that could be associated with withe and white spotting phenotypes. For this purpose, fiber samples and skin biopsies from animals with different coat color phenotypes were collected. Then, RNA was extracted and total cDNA was obtained. cDNA was used as template for PCRreactions that fully covered the coding region and flanquing 5´and 3´UTR. We sequenced the MITF-M complete coding region of three white, two white spottingand five colored llamas. Two distinct isoforms were found in both colored and white/white spotted animals. MITF-M () which consists of a coding regionof 1242 bp, corresponding to 414 amino acids, and MITF-M (+) with an insertion of 18 pb in nucleotides 564?582. Only four mutations were observed: two SNPs that represent synonymous mutations and two non-synonymous SNPs (c.110 C > A and c.575 C > T). Mutation c.575 C > T was observed in both, colored and white phenotypes; therefore it is unlikely to be coat-color-associated. On the contrary, mutation c.110 C > A introduces a Tyrosine instead of a Serinein a highly conserved position. Since allele A was only observed in a white animal and was not found in colored llamas, this SNP deserves a more thorough study. However, it appears that mutations in the MITF coding region are not mainly responsible for white/white spotting phenotypes. Regulatory mutations affecting expression or different genes could explain these phenotypes in llamas.