Intronic variants of MITF (rs7623610) and CREB1 (rs10932201) genes may enhance splicing efficiency in human melanoma cell line

We previously reported that intronic single nucleotide variations (SNVs) in MITF (c.938-325G>A, rs7623610) and CREB1 (c.303+373G>A, rs10932201) genes were associated with risk, aggressiveness, and prognosis of cutaneous melanoma (CM). In this study, we investigated the influence of the above SNVs in splicing patterns and efficiency. We constructed minigenes with wild type and variant alleles from MITF and CREB1 to assess the effect of the SNVs on splicing. The minigenes were transfected in the human melanoma cell line (SK-MEL-28). RT-PCR and DNA sequencing investigated the constructs' splicing patterns. Minigenes constructs' splicing efficiency and HNRNPA1 and SF1 splicing genes' expression were investigated by qPCR. We found that MITF and CREB1 SNVs did not alter the splicing pattern, but they influenced the splicing efficiency. MITF-A (p= 0.03) and CREB1-A (p= 0.005) variant minigenes yielded an increase of mRNA generated from the constructions. Additionally, lower mRNA levels of HNRNPA1 and SF1 were seen in the variant minigenes MITF-A (p= 0.04) and CREB1-A (p= 0.005). We described for the first time the potential importance of MITF rs7623610 and CREB1 rs10932201 SNVs in splicing efficiency and its relationship with CM.