Expression and contribution of microphthalmia-associated transcription factor to the melanin deposition in Liancheng white ducks

The present study investigates the expression of microphthalmia-associated transcription factor(MITF) and its contribution to the melanin deposition in Liancheng white ducks.Nested PCR was used to clone the MITF gene sequence from the skin tissue of female Liancheng white ducks.Ultraviolet spectrophotometry was used to detect the melanin deposition.MITF mRNA expression and melanin deposition in different tissues and organs were detected and their correlation was analyzed.The MITF gene(GenBank number: MG516570) was 1 323 bp in length,contains a complete CDS region(34-1 323 bp) and codes 429 amino acids with 100% homology to the MITF of Anas platyrhynchos and over 95% homology to those of Gallus gallus and Coturnix japonica.Genetic evolution analysis reveals a close relationship of Liancheng white ducks with A.platyrhynchos,and also to lesser extents with Anser cygnoides,silky fowl and G.gallus,as well as Sus scrofa,Ovis aries and other mammals.Real-time quantitative PCR(qPCR) analysis demonstrated that MITF was expressed in skin,gizzard,liver,kidney and muscle,and of these tissues,its expression was the highest in the skin tissue(skin>gizzard>liver>kidney>muscle).Ultraviolet spectrophotometry showed that melanin deposition was positively correlated with the MITF expression level in these five tissues and organs(P<0.05).Together,these results demonstrated a tissue-specific pattern of MITF expression and a positive correlation between MITF expression and melanin deposition,indicating that MITF expression may contribute to the melanin deposition in Liancheng white ducks.

Cloning of a microphthalmia-associated transcription factor gene and its functional analysis in nacre formation and melanin synthesis in Hyriopsis cumingii

Microphthalmia-associated transcription factor(MITF)is an essential transactivator in melanin synthesis.To characterize the role of MITF in the pearl mussel Hyriopsis cumingii,the MITF homolog of H.cumingii was isolated.The full-length HcMitf cDNA consisted of a 1332-bp with an open reading frame that encode for a 443 amino acid protein that contain a conserved basic helix-loop-helix zipper domain.The HcMitf was found to widespread tissue distribution but expression was higher in purple mussels than in white mussels,mostly in mantle,liver,kidney,gill,and foot with the exception of the adductor mussel.HcMitf and its downstream gene tyrosinase(HcTyr)were highly expressed at the nacre deposition stage after implantation of mantle tissue to produce pearls.Using RNA interference,the expression of HcMitf was reduced by 78%(P<0.01)and expression of HcTyr was also significantly suppressed and consequently total melanin content was decreased(P<0.05).The results suggest that HcMitf plays an important role in melanin synthesis,nacre formation and shell pigmentation in the H.cumingii.

AstragalosideⅣimproves melanocyte differentiation from mouse bone marrow mesenchymal stem cells

Vitiligo results in an autoimmune disorder destructing skin pigment cells,melanocytes(Mcs).This study aimed to investigate whether Astragaloside IV(AIV)could efficiently induce differentiation of bone marrow mesenchymal stem cells(BMMSCs)into Mcs.BMMSCs were induced and differentiated into Mcs with 0.1,0.2,and 0.4 mg/L AIV during 150-day.Morphologic changes of differentiated cells were observed.Levels of some melanocytic specific genes(TRP-1,TRP-2,MART-1,Mitf)were measured with quantitative polymerase chain reaction(qPCR)at 90,120,and 150 days of induction.After 90-day induction,the differentiated cells with 0.4 mg/L AIV demonstrated the typical morphology of Mcs,positive 3,4 dihydroxyphenylalanine staining,and positive staining of TRP-1,TRP-2,MART-1,and Mitf.After 90-and 120-days’induction with 0.4 mg/L AIV,TRP-1 expression was significantly elevated(p<0.01),and TRP-2 expression was significantly increased in 0.4 mg/L AIV-treated group compared to negative control(p<0.01),0.1 mg/L(p<0.01),and 0.2 mg/L(p<0.01)AIV-treated groups.Moreover,MART-1 expression was significantly up-regulated in 0.4 mg/L AIV-treated group compared to negative control,but without difference compared to 0.1 mg/L(p>0.05)and 0.2 mg/L(p>0.05)AIV-treated groups.During 90 to 150-day induction,there were no significant differences for Mitf levels between AIV-treated groups and negative control(p>0.05).In conclusion,90-day induction with 0.4 mg/L AIV up-regulated TRP-1,TRP-2,and MART-1 expression,indicating that AIV can efficiently induce Mcs differentiation from BMMSCs.These results provide experimental and theoretic evidence for AIV application in clinical vitiligo repigmentation treatment.