Gene Regulation through mRNA Expression

In eukaryotes, gene expression is achieved by four steps: transcription, processing, nuclear export, and translation. Each step requires multiple factors, and frequently two or more pathways are used by a single gene, enabling strictly regulated gene expression. Importantly, eukaryotes, taking advantage of the separated structures of the nucleus and the cytoplasm, have evolved complex and organized mRNA processing mechanisms that permit sophisticated biological activity. The processes are much more complicated than those found in prokaryotes, in which transcription and translation occur linearly in time and place. Here, we review gene expression, focusing on mRNA processing in the nucleus and the gene regulatory systems found at each step. Combination of gene regulation shows the typical phenotype in each cell. Further understanding of the uncertain mechanisms will uncover the gene regulation through mRNA expression.

Novel SLC30A2 mutations in the pathogenesis of transient neonatal zinc deficiency

Importance:Transient neonatal zinc deficiency(TNZD)occurs in breastfed infants due to abnormally low breast milk zinc levels.Mutations in the solute carrier family 30 member 2(SLC30A2)gene,which encodes the zinc transporter ZNT2,cause low zinc concentration in breast milk.Objective:This study aimed to provide further insights into TNZD pathophysiology.Methods:SLC30A2 sequencing was performed in three unrelated Japanese mothers,whose infants developed TNZD due to low-zinc milk consumption.The effects of the identified mutations were examined using cell-based assays and luciferase reporter analysis.Results:Novel SLC30A2 mutations were identified in each mother.One harbored a heterozygous missense mutation in the ZNT2 zinc-binding site,which resulted in defective zinc transport.The other two mothers exhibited multiple heterozygous mutations in the SLC30A2 promoter,the first mutations in the SLC30A2 regulatory region reported to date.Interpretation:This report provides new genetic insights into TNZD pathogenesis in breastfed infants.

Glycosylation engineering of therapeutic IgG antibodies： challenges for the safety, functionality and efficacy

Glycosylation of the Fc region of IgG has a profound impact on the safety and clinical efficacy of therapeutic antibodies. While the biantennary complex.type oligosaccharide attached to Asn297 of the Fc is essen- tial for antibody effector functions, fucose and outer-arm sugars attached to the core heptasaccharide that gen- erate structural heterogeneity （glycoforms） exhibit unique biological activities. Hence, efficient and quan- titative glycan analysis techniques have been increas- ingly important for the development and quality control of therapeutic antibodies, and g｜ycan profiles of the Fc are recognized as critical quality attributes. In the past decade our understanding of the influence of glycosy- lation on the structure/function of IgG-Fc has grown rapidly through X-ray crystallographic and nuclear magnetic resonance studies, which provides possibili- ties for the design of novel antibody therapeutics. Fur- thermore, the chemoenzymatic glycoengineering approach using endoglycosidase-based glycosyn- thases may facilitate the development of homogeneous IgG glycoforms with desirable functionality as next- generation therapeutic antibodies. Thus, the Fc glycans are fertile ground for the improvement of the safety,functionality, and efficacy of therapeutic IgG antibodies in the era of precision medicine.

Sequence Similarity and Functional Relationship Among Eukaryotic ZIP and CDF Transporters

ZIP （ZRT/IRT-like Protein） and CDF （Cation Diffusion Facilitator） are two large metal transporter families mainly transporting zinc into and out of the cytosol. Several ZIP and CDF transporters have been characterized in mammals and various model organisms, such as yeast, nematode, fruit fly, and zebrafish, and many candidate genes have been identified by genome projects. Unexpected functions of ZIP and CDF transporters have been recently reported in some model organisms, leading to major advances in our understanding of the functions of mammalian counterparts. Here, we review the recent information on the sequence similarity and functional relationship among eukaryotic ZIP and CDF transporters obtained from the representative model organisms.