The ASIP gene in the Llama (Lama glama) : alternative transcripts, expression and relation with color phenotypes

The Agouti gene (ASIP) is one of the most important genes for coat color determination in mammals. It has a complex structure with several promoters and alternative non-coding first exons that are transcribed into mRNAs with different 5́UTR. These mRNA isoforms regulate the temporal and spatial expression of the gene, producing diverse pigmentation patterns. Here, we studied ASIP transcriptional variants and their expression in the skin of llamas with different coat color phenotypes. We also described the ASIP locus, including promoter usage and the splicing events that originate each transcript variant. Using 5́RACE-PCR we isolated seven ASIP transcripts with alternative 5’UTR, where exons 1A, 1A’, 1C, 1D, and a novel non-coding exon 1A” were identified. Additionally, new alternative spliced forms were found. The diversity of ASIP 5’UTRs is originated by a complex pattern of alternative promoter usage, multiple transcription start sites and splicing events that include exon skipping and alternative 3’ splicing site selection. We found that ASIP was highly expressed in llamas with white and brown phenotypes while black animals presented very low expression. The main responsible for this difference was a fusion transcript between ASIP and NCOA6 genes, which was present in the skin of white and brown llamas but not in the black ones. The rest of ASIP transcripts presented very low expression in the skin, indicating that the main regulation point for ASIP gene expression is at the transcriptional level. Nevertheless, the characteristics of the 5’UTRs sequences suggest that alternative transcripts could be regulated differently at the protein synthesis level.

Bibliographic Details

Main Authors:	Anello, Melina, Daverio, Maria Silvana, Rodriguez, S.S., Romero, Sandra Raquel, Renieri, Carlo, Vidal Rioja, Lidia Beatriz, Di Rocco, Florencia
Format:	info:ar-repo/semantics/artículo biblioteca
Language:	eng
Published:	Elsevier 2021-10-19T12:42:34Z
Subjects:	Llama, Fenotipos, Genética, Expresión Génica, Llamas, Phenotypes, Genetics, Gene Expression, Agouti Gene, ASIP Gene,
Online Access:	http://hdl.handle.net/20.500.12123/10524 https://www.sciencedirect.com/science/article/abs/pii/S0378111921006132 https://doi.org/10.1016/j.gene.2021.146018
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