ASIP: TRANSCRIPTS AND EXPRESSION IN LLAMAS WITH DIFFERENT COAT COLOR

ANELLO MELINA; VIDAL RIOJA LIDIA; DAVERIO MARÍA SILVANA; CARLO RENIERI; ROMERO SANDRA; DI ROCCO, FLORENCIA

Lleida

Congreso; 37th International Conference on Animal Genetics; 2019

ISAG

The Agoutí gene (ASIP) is one of the most important genes forcoat color determination in mammals. It has a complex structure withdifferent promoters and alternative non-coding first exons that are transcribed into mRNAs with different 5′UTR. Studies in domestic animalsindicate these transcripts can control pigment distribution. Otherwise,white coat is usually produced by mutations in KIT, MITF and TYRgenes. However, this phenotype has also been associated with overexpression of ASIP in some species. In llamas (Lama glama), the molecular mechanism responsible for white is still unknown. We have recently studied the coding regions of KIT, MITF, TYR and ASIP, but nomutations were found to be associated with white coat in this species.Here, we characterized ASIP transcripts and studied their expressionlevels in the skin of llamas to further understand the role of ASIP incoat color determination. Skin biopsies were taken from white, pheomelanic (reddish brown) and eumelanic (black) llamas and total RNAwas extracted. Then PCR-RACE was used to amplify the 5′UTRs ofASIP and these products were cloned and sequenced. Seven ASIP transcripts that differed in the 5′UTR were found. Most of them exhibiteda structure similar to some ASIP transcripts already described in othermammalian species and we identified the homologous exons 1A, 1A?,2A, 3A, and 1C. Additionally, one transcript (T6) presented a 5′UTRof 120 bp that showed similarity with NCOA6 gene. Then, we studiedthe global expression of ASIP by qPCR in the 3 phenotypic groups.White and brown groups showed an overexpression of ASIP in comparison to black (P < 0.0001) but no significant difference between whiteand brown was observed. Besides, we analyzed how T6 contributes tothe global expression and found it was highly expressed in white andbrown but not detected in black. Therefore, T6 is contributing to the ISAG 2019 Abstract Book 166expression of ASIP in white and brown while other transcripts accountfor ASIP overall expression in black llamas. These results suggest ASIPtranscripts have a role in coat color determination and we will carry outa more thorough study to evaluate the expression of each transcript andassess their contribution to color.