Dickkopf-1 (DKK1) is an inhibitor of canonical Wnt signaling pathway and regulates hair follicle morphogenesis and cycling. To investigate the potential involvement of DKK1 in wool production and quality traits, we characterized the genomic structure of ovine DKK1, performed polymorphism detection and association analysis of ovine DKK1 with wool production and quality traits in Chinese Merino. Our results showed that ovine DKK1 consists of four exons and three introns, which encodes a protein of 262 amino acids. The coding sequence of ovine DKK1 and its deduced amino acid sequence were highly conserved in mammals. Eleven single nucleotide polymorphisms (SNPs) were identified within the ovine DKK1 genomic region. Gene-wide association analysis showed that SNP5 was significantly associated with mean fiber diameter (MFD) in the B (selected for long wool fiber and high-quality wool), PW (selected for high reproductive capacity, high clean wool yield and high-quality wool) and U (selected for long wool fiber with good uniformity, high wool yield and lower fiber diameter) strains (p < 4.55 × 10⁻³ = 0.05/11). Single Nucleotide Polymorphisms wide association analysis showed that SNP8 was significantly associated with MFD in A strain and fleece weight in A (selected for large body size), PM (selected for large body size, high reproductive capacity and high meat yield) and SF (selected for mean fiber diameter less than 18 μm and wool fiber length between 5 and 9 cm) strains (p < 0.05), SNP9 was significantly associated with curvature in B and U strains (p < 0.05) and SNP10 was significantly associated with coefficient of variation of fiber diameter in A, PW and PM strains and standard deviation of fiber diameter in A and PM strains (p < 0.05). The haplotypes derived from these 11 identified SNPs were significantly associated with MFD (p < 0.05). In conclusion, our results suggest that DKK1 may be a major gene controlling wool production and quality traits, also the identified SNPs (SNPs5, 8, 9 and 10) might be used as potential molecular markers for improving sheep wool production and quality in sheep breeding.

POU domain class 2 transcription factor 3 (POU2F3) plays an important role in keratinocyte proliferation and differentiation. Our previous study identified four sheepPOU2F3transcript variants (POU2F3-1,POU2F3-2,POU2F3-3, andPOU2F3-4), encoding three POU2F3 protein isoforms (POU2F3-1, POU2F3-2, and POU2F3-3). However, the functional differences among the three POU2F3 isoforms remain unknown. The objective of this study was to determine the tissue expression pattern of the fourPOU2F3transcript variants in sheep and to investigate the functional differences in cell proliferation among the three POU2F3 isoforms. Quantitative RT-PCR analysis showed that the fourPOU2F3transcripts were ubiquitously expressed in all tested adult sheep tissues, andPOU2F3-1exhibited higher expression level than the other threePOU2F3transcript variants in skin (P < 0.05). Cell proliferation assay showed that overexpression of any one of the three POU2F3 isoforms significantly inhibited the proliferation of sheep fetal fibroblasts and HaCaT cells at 48 and 72 h after transfection (P < 0.05). POU2F3-3 had less inhibitory effect on cell proliferation than POU2F3-1 and POU2F3-2 (P < 0.05), and POU2F3-1 and POU2F3-2 had similar inhibitory effects (P > 0.05). Dual luciferase reporter assays demonstrated that overexpression of any one of the three POU2F3 isoforms significantly inhibited the promoter activities of keratin 14 (KRT14) and matrix metalloproteinase 19 (MMP19) genes (P < 0.05). POU2F3-3 had less inhibitory effect on the promoter activities ofKRT14andMMP19genes than POU2F3-1 and POU2F3-2 (P < 0.05), and POU2F3-1 and POU2F3-2 had similar inhibitory effects (P > 0.05). These results suggest three sheep POU2F3 isoforms have similar functional effects, but to a different extent.

Graptemys ouachitensis (CAGLE, 1953) belongs to the Graptemys genus, the Emydidae family, and the Testudines order. This study involved sequencing the complete mitochondrial genome (mitogenome) of G. ouachitensis using next-generation sequencing, and analyzing the essential characteristics, and phylogenetic relationship. The results revealed that the G. ouachitensis mitogenome was 16,674 bp in length (A: 34.1%, C: 26.0%, G: 13.0%, T: 26.9%) and included 22 tRNAs, 13 protein-coding genes, two ribosomal RNA genes, and a non-coding control region (GenBank accession: NC071766). The genome composition of G. ouachitensis presented a slight A + T bias (61.0%) and exhibited a positive AT skew (0.118) and a negative GC skew (-0.333). A phylogenetic analysis based on the complete mitogenome indicated that the G. ouachitensis was more closely associated with Malaclemys terrapin than the other eight known Emydidae species. Thus, our findings present a novel mitogenome at the species level. This study introduces the first complete mitogenome of G. ouachitensis, providing valuable molecular information for phylogenetic and conservation genetics analyses of G. ouachitensis.