Genome-wide analysis of zinc- and iron-regulated transporter-like protein family members in apple and functional validation of ZIP10.

Deficiency of zinc (Zn) and iron (Fe) is common in apple grown in orchards, which affects fruit yield and quality. However, the mechanisms of absorption and transport of Zn and Fe in apples are still unclear. In the present study, we aimed to identify MdZIP genes and explore the mechanism of response of MdZIPs to Zn and Fe deficiencies. Eighteen Zn- and Fe-regulated transporter-like protein (ZIP) family members were identified in apple (Malus domestica L.) and named according to their chromosomal location. Phylogenetic analysis divided MdZIPs into four groups, and the most closely related MdZIPs in the phylogenetic tree showed similar gene structures and protein motifs. Expression pattern analysis indicated that ZIP genes in apple were differentially expressed among tissues and developmental stages under Zn and Fe deficiency. The overexpression of MdZIP10 increased the content of Zn and Fe in Arabidopsis thaliana L. and MdZIP10 played crucial roles in the uptake and transport of Zn and Fe. MdZIP10 was able to rescue growth of Zn2+ and Fe2+ uptake defective yeast mutants under Zn2+ and Fe2+ deficient conditions, respectively. Symptoms of Zn and Fe deficiency were alleviated in the MdZIP10 transgenic plants. The expression of genes related to Fe and Zn uptake and transport was induced in the MdZIP10 transgenic plants, thereby stimulating endogenous Fe and Zn uptake and transport mechanisms. The present study lays the foundation for future functional analysis of ZIP genes in apple.

Utility of Serum IgG4 Levels in a Multiethnic Population.

BACKGROUND: IgG4-related disease (IgG4-RD) is a recently recognized condition defined by characteristic histopathologic findings in affected organs. Serum IgG4 concentration is often but not always elevated. The sensitivity and specificity of serum IgG4 vary greatly across studies and has been anecdotally associated to ethnicity. Our study was conducted to investigate the difference in serum IgG4 levels between Asian and non-Asian patients with IgG4-RD. METHODS: This is a single-center retrospective study of 26 Asian and 10 non-Asian patients with histologically confirmed IgG4-RD. Serum IgG4 levels, clinical features and other laboratory findings were compared between the 2 groups, 31 Asian and 11 non-Asian patients with non-IgG4-RD rheumatic diseases were randomly identified to evaluate test characteristics of serum IgG4 measurement. RESULTS: Median serum IgG4 at time of diagnosis was significantly higher in Asian (median = 11.2g/L, interquartile range: 4.6-19.7) than non-Asian patients (median = 2.9g/L, interquartile range: 0.7-5.4, P = 0.0094), as well as the median serum IgG and total protein. Asian patients had more eosinophilia and polyclonal hypergammaglobulinemia than non-Asian patients (P = 0.016 and 0.001, respectively). Test sensitivity was higher in Asian (96%) than non-Asian patients (67%), whereas test specificity was higher in non-Asian patients (91% versus 71%). CONCLUSION: Asian patients with IgG4-RD have more exuberant serum IgG4, IgG and polyclonal hypergammaglobulinemia than non-Asian patients; the mechanism of this difference requires further study. These findings have significant clinical importance and must be accounted for in the diagnostic workup of patients in multiethnic settings.