Effects Of Melatonin On Expression Of Let-7 Family And Its Target Genes In Skin Of Cashmere Goats

Inner Mongolia cashmere goats are excellent local genetic germplasm resources in the autonomous region and have excellent villous production performance.Both melatonin and miRNAs can play an important regulatory role in the growth of cashmere goats.Let-7 was one of the first discovered miRNAs and was found to be highly expressed in the skin of cashmere goats and was associated with the periodic development of skin hair follicles.Most studies have analyzed the regulation of single or a few members of the let-7 family and their target genes,and fewer studies have involved the study of co-expression patterns of the entire let-7 family members and their target genes.To explore the effects of melatonin on the periodic expression of let-7 family melbers and their target genes in the skin of Inner Mongolian cashmere goats.This study carried out the following two researches on the skin tissue of cashmere goats:1.In this study,six adult female Inner Mongolia Cashmere goats were selected and divided equally and randomly into two groups,melatonin implantation group and non-implantation group.Collecting individual skin tissue of the body side of cashmere goats for 12 consecutive months.The expression of eleven members of let-7 family was quantified by reverse transcription-real time polymerase chain reaction(qRT-PCR)in the skin tissue.The expression changes of the target genes of let-7 family were analyzed using the RNA-Seq technique.The results showed that 1)Melatonin up-regulated the expression of let-7b,let-7e and let-7a-3p(P<0.05),down-regulated the expression of let-7f,let-7g,let-7c,let-7a-5p,let-7d and miR-98(P<0.05).2)In April,melatonin up-regulated the expression of let-7g,let-7i and miR-98,down-regulated the expression of target genes such as PTGS2 and PLCG1.It down-regulated the expression of let-7a-5p,let-7b and let-7c,up-regulated the expression of target genes such as TGIF2 and RBL1.3)In June,melatonin down-regulated the expression of let-7g,let-7i and miR-98,up-regulated the expression of target genes such as PTGS2,PLCG1 and SRC;It up-regulated the expression of let-7a-5p,let-7b and let-7c,down-regulated the expression of target genes such as GDF5,TGIF2 and RBL1.4)The targets were mainly involved in VEGF,TGF-?,Oxytocin and NF-kappa B signaling pathways,and played an important role in cell processes,hormone regulation and regulation of transcription factors.In summary,Melatonin may affect the expression of the corresponding target genes by changing the expression level of members of the let-7 family.It plays an important role in the periodic growth of skin hair follicles.These results provided a theoretical basis for further revealing the molecular mechanism by which melatonin mediates miRNAs to affect cashmere growth.2.Comparing the RNA-Seq data of cashmere goat skin,long-light period(March to August)has 1803 differentially expressed genes,which are mainly enriched in ECM-receptor interaction,Wnt signaling pathway,Complement and coagulation cascades,Melanogenesis,Signaling pathways regulating pluripotency of stem cells and other important signaling pathways;In the short-light period(September to February),there are 551 differentially expressed genes,which are mainly enriched in Complement and coagulation cascades,Leukocyte transendothelial migration,B cell receptor signaling pathway,Cytokine-cytokine receptor interaction and other important signaling pathways.All DEGs were analyzed using the WGCNA method,and 5 important modules related to the growth and development of skin hair follicles were screened,including 59 core genes.It can be used as a candidate gene for melatonin to promote the growth of villi,and provide a theoretical basis for further revealing the molecular mechanism of melatonin to promote villus growth.