ALPACA FGF5: HYPOTHETICAL POST-TRASCRIPTIONAL READTHROUGH REGULATION IN SKIN BIOPSIES

Two different phenotypes are described in alpaca, identified as Suri and Huacaya which differ for the type of the fleece. The Huacaya fleece is characterised by compact, soft and highly crimped fibres while the suri fleece is longer, straight, less-crimped and lustrous. In our study, the Fibroblast growth factor 5 (FGF5) was investigated as a possible candidate gene for hair length in alpaca (Vicugna pacos). Total RNA purified from alpaca Suri and Huacaya skin biopsies, was reverse transcribed to cDNA using oligo dT priming and subsequently amplified by using FGF5 specific primers. Further, the resulting amplicons were cloned and sequenced. As previously identified in others mammals, our results also show that the alpaca FGF5 gene, give rise to a short (FGF5S) and a long (FGF5) isoform. Interestingly, in the long isoform, we observed a point mutation (i.e. a transition C>T at position 499 downstream of the ATG codon) able to generate a Premature Stop Codon (PSC). The highly conserved nucleotide and aminoacid sequence after PSC suggested, and western blot analysis confirmed, a Readthroug event (RT). The analysis of mRNA sequence revealed motifs and characteristics that correlate with mRNA that undergoing RT (i.e. the higher “leakyness” of UGA Stop Codon, leakyness” due to the position -1, -2 in respetc the UGA PSC with purines and +4 with pyrimidines, presence of suzesky sequences, pseudoknots in 3'UTR and tandem repeat Stop Codon after the canonical TAA, presence of long intron in the gene and long 3'UTR). To the best of our knowledge this is the first case of readtrhough event on PSC reported for FGF5 gene.