DOCK3

The objective of this study was to investigate the genetic diversity, popula-tion structure and whole-genome selection signatures of Luxi cattle to reveal its ge-nomic characteristics in terms of meat and carcass traits, skeletal muscle development, body size, and other traits.

To further analyze the genomic characteristics of Luxi cattle, this study se-quenced the whole-genome of 16 individuals from the core conservation farm in Shan-dong region, and collected 174 published genomes of cattle for conjoint analysis. Fur-thermore, three different statistics (pi, Fst, and XP-EHH) were used to detect potential positive selection signatures related to selection in Luxi cattle. Moreover, Gene Ontol-ogy (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrich-ment analyses were performed to reveal the potential biological function of candidate genes harbored in selected regions.

The results showed that Luxi cattle had high genomic diversity and low in-breeding levels. Using three complementary methods (pi, Fst and XP-EHH) to detect the signatures of selection in the Luxi cattle genome, there were 2,941, 2,221 and 1, 304 potentially selected genes identified, respectively. Furthermore, there were 45 genes annotated in common overlapping genomic regions covered 0.723 Mb, including PLAG1, DOCK3, EFNA2, DAZAP1, RALGAPA1, MED13, and PDSS2, most of which were enriched in pathways related to muscle growth and differentiation and im-munity.

In this study, we provided a series of genes associated with important economic traits were found in positive selection regions, and a scientific basis for the scientific conservation and genetic improvement of Luxi cattle.

MOCA1 encodes the last key glucuronosyltransferase for ionic stress sensor glycosyl inositol phosphoryl-ceramide (GIPCs) biosynthesis in Arabidopsis, which indicates that the MOCA gene family play important role in plant tolerance to salt stress. However, the isolation and function of MOCAs in staple crops have not been reported and the downstream targets of MOCAs in salt stress tolerance signalling pathway are not clear. In this study, we identified 110 MOCA genes in wheat which were classified into five clades and they differed in gene structure, protein length, conserved motifs and expression profiles in different tissues and under salt stress. TaMOCA1 was selected for further functional study in response to salt stress. TaMOCA1 was rapidly induced by NaCl treatment. The 35S::TaMOCA1-GFP construction showed the cell nucleus and cytoplasm location in wheat protoplast. TaMOCA1 over-expressing Arabidopsis seedlings formed longer primary roots and more lateral roots than the wild type ones under 50 mM NaCl treatment. The over-expressing Arabidopsis had higher expression levels of HKT1, but lower expression levels of NHX1 and SOS genes than the wild type. Also, the transgenic plants had higher SOD activity and lower MDA content than the wild Arabidopsis seedling under salt stress. These results may indicate that TaMOCA1 increases salt stress tolerance through decreasing Na⁺ loading from the xylem parenchyma cells to the xylem via SOS1 and HKT1, hence lowering root-to-shoot delivery of Na? and superior antioxidant ability. All these results lay a foundation for further functional study of MOCAs in wheat.

DOCK (dedicator of cytokinesis) is an 11-member family of typical guanine nucleotide exchange factors (GEFs) expressed in the brain, spinal cord, and skeletal muscle. Several DOCK proteins have been implicated in maintaining several myogenic processes such as fusion. We previously identified DOCK3 as being strongly upregulated in Duchenne muscular dystrophy (DMD), specifically in the skeletal muscles of DMD patients and dystrophic mice. Dock3 ubiquitous KO mice on the dystrophin-deficient background exacerbated skeletal muscle and cardiac phenotypes. We generated Dock3 conditional skeletal muscle knockout mice (Dock3 mKO) to characterize the role of DOCK3 protein exclusively in the adult muscle lineage. Dock3 mKO mice presented with significant hyperglycemia and increased fat mass, indicating a metabolic role in the maintenance of skeletal muscle health. Dock3 mKO mice had impaired muscle architecture, reduced locomotor activity, impaired myofiber regeneration, and metabolic dysfunction. We identified a novel DOCK3 interaction with SORBS1 through the C-terminal domain of DOCK3 that may account for its metabolic dysregulation. Together, these findings demonstrate an essential role for DOCK3 in skeletal muscle independent of DOCK3 function in neuronal lineages.