A light-sensitive mutation in Arabidopsis LEW3 reveals the important role of N-glycosylation in root growth and development
JOURNAL OF EXPERIMENTAL BOTANY
Authors: Manzano, Concepcin; Pallero-Baena, Mercedes; Silva-Navas, J.; Navarro Neila, Sara; Casimiro, Ilda; Casero, Pedro; Garcia-Mina, Jose M.; Baigorri, Roberto; Rubio, Lourdes; Fernandez, Jose A.; Norris, Matthew; Ding, Yiliang; Moreno-Risueno, Miguel A.; del Pozo, Juan C.
Abstract
Plant roots have the potential capacity to grow almost indefinitely if meristematic and lateral branching is sustained. In a genetic screen we identified an Arabidopsis mutant showing limited root growth (lrg1) due to defects in cell division and elongation in the root meristem. Positional cloning determined that lrg1 affects an alpha-1,2-mannosyltransferase gene, LEW3, involved in protein N-glycosylation. The lrg1 mutation causes a synonymous substitution that alters the correct splicing of the fourth intron in LEW3, causing a mix of wild-type and truncated protein. LRG1 RNA missplicing in roots and short root phenotypes in lrg1 are light-intensity dependent. This mutation disrupts a GC-base pair in a three-base-pair stem with a four-nucleotide loop, which seems to be necessary for correct LEW3 RNA splicing. We found that the lrg1 short root phenotype correlates with high levels of reactive oxygen species and low pH in the apoplast. Proteomic analyses of N-glycosylated proteins identified GLU23/PYK10 and PRX34 as N-glycosylation targets of LRG1 activity. The lrg1 mutation reduces the positive interaction between Arabidopsis and Serendipita indica. A prx34 mutant showed a significant reduction in root growth, which is additive to lrg1. Taken together our work highlights the important role of N-glycosylation in root growth and development.
Downregulation of leucine-rich-alpha-2-glycoprotein 1 expression is associated with the tumorigenesis of head and neck squamous cell carcinoma
ONCOLOGY REPORTS
Authors: Wang, Yongping; Chen, Chen; Hua, Qingquan; Wang, Lei; Li, Fen; Li, Man; Mei, Zhidan; Zhou, Tao; Xiao, Bokui; Tao, Zezhang
Abstract
Leucine-rich-alpha-2-glycoprotein 1 (LRG1) is considered as a potential biomarker as it is aberrantly expressed in various malignancies. However, there is limited information regarding its role in head and neck squamous cell carcinoma (HNSCC). In the present study, we aimed to explore the expression pattern of LRG1 in HNSCC and its clinicopathological significance. We first analyzed LRG1 gene expression in HNSCC by investigating data obtained from the Gene Expression Omnibus (GEO) database. The results showed that LRG1 was downregulated in HNSCC tissues and its expression level was negatively related to tumor T and N stages and degree of malignancy. Then, we further tested a tissue microassay and clinical samples, respectively, by immunohistochemical staining and western blotting. Consistently, the results revealed that LRG1 expression was decreased in tumor tissues regardless of the grade of the tumor. Moreover, the protein level of LRG1 showed slight differences among four T stages or three N stages. In addition, there were no significant associations between LRG1 protein expression and other clinicopathological parameters such as gender, age, tumor location and clinical staging. These findings imply that downregulation of the expression of LRG1 is correlated with tumorigenesis but not with the development of HNSCC, indicating the potential clinical value of LRG1 in the early diagnosis of HNSCC.