Mutations in the secreted metalloproteinase ADAMTS10 cause recessive Weill-Marchesani syndrome (WMS), comprising ectopia lentis, short stature, brachydactyly, thick skin and cardiac valve anomalies. Dominant WMS caused by FBN1 mutations is clinically similar and affects fibrillin-1 microfibrils, which are a major component of the ocular zonule. ADAMTS10 was previously shown to enhance fibrillin-1 assembly in vitro. Here, Adamts10 null mice were analyzed to determine the impact of ADAMTS10 deficiency on fibrillin microfibrils in vivo. An intragenic lacZ reporter identified widespread Adamts10 expression in the eye, musculoskeletal tissues, vasculature, skin and lung. Adamts10 mice had reduced viability on the C57BL/6 background, and although surviving mice were slightly smaller and had stiff skin, they lacked brachydactyly and cardiovascular defects. Ectopia lentis was not observed in Adamts10 mice, similar to Fbn1 mice, most likely because the mouse zonule contains fibrillin-2 in addition to fibrillin-1. Unexpectedly, in contrast to wild-type eyes, Adamts10 zonule fibers were thicker and immunostained strongly with fibrillin-2 antibodies into adulthood, whereas fibrillin-1 staining was reduced. Furthermore, fibrillin-2 staining of hyaloid vasculature remnants persisted post-natally in Adamts10 eyes. ADAMTS10 was found to cleave fibrillin-2, providing an explanation for persistence of fibrillin-2 at these sites. Thus, analysis of Adamts10 mice led to identification of fibrillin-2 as a novel ADAMTS10 substrate and defined a proteolytic mechanism for clearance of ocular fibrillin-2 at the end of the juvenile period.

Metal Tolerance Proteins (MTPs) are the class of membrane proteins involved in the transport of metals, mainly Zn, Mn, Fe, Cd, Co and Ni, and confer metal tolerance in plants. In the present study, a comprehensive molecular analysis of rice MTP genes was performed to understand the evolution, distribution and expression dynamics of MTP genes. Exploration of the whole genome re-sequencing information available for three thousand rice genotypes highlighted the evolution and allelic diversity of MTP genes. Based on the presence of non-synonymous single nucleotide polymorphism (SNP), MTP1, MTP6, MTP8 and MTP9 were found to be the most conserved genes. Furthermore, results showed localization of MTP1, MTP8.1 and MTP9, and MTP11, respectively with QTLs/m-QTLs for Zn and Cd accumulation, making these genes promising candidates to understand the QTL regulation. Expression profiling of the entire set of 10 MTP genes revealed root and shoot specific expressions of MTP9 and MTP8.1, respectively, under all tested vegetative stages. Expression of seed-specific MTPs increased as seed maturation progressed, which revealed their potential role in transporting metals during seed filling. Upon exposure to harmful heavy metals, expression of most MTP genes decreased in root and increased in shoot, suggests that different mechanisms are being employed by MTPs in different tissues. Contrastingly, only a few MTPs were found to be responsive to Fe and/or Zn starvation conditions. The extensive analysis of MTPs presented here will be helpful in identifying candidate MTP genes for crop biofortification and bioremediation purposes.

ADAMTS5 (aggrecanase-2) is an extracellular matrix-degrading protease implicated in cartilage destruction in arthritis. Our goals were to determine expression sites of Adamts5 in the murine musculoskeletal system and in an ex vivo joint inflammation model. In mice with an intragenic LacZ reporter controlled by the Adamts5 promoter, b-galactosidase staining was used to identify Adamts5 expressing cells. Mice expressing one wild-type Adamts5 allele were used to determine distribution of Adamts5 mRNA, cleaved aggrecan and versican, and the ADAMTS5 activating enzymes furin and PACE4. Quantitative RT-PCR and immunoblotting were used to validate the immunohistochemistry results. Adamts5 was expressed in mouse synovium, tenosynovium, bone marrow sinusoids, tendons, ligaments, ligament insertions, periosteal cells, and bone vasculature. In knee joint explants treated with IL-1a and TNFa, Adamts5 expression was induced in tenocytes, synovium, and in patellar, but not femoral or tibial articular cartilage. In contrast, increased proteoglycan breakdown in tibial and femoral articular cartilage was associated with increased immunohistochemical staining of PACE4 and furin. These studies identify diverse cell types in the musculoskeletal system that express Adamts5. They also suggest that Adamts5 induction in joint components other than cartilage, and its post-translational activation by PACE4 and/or furin may be important in the pathophysiology of arthritis. ß

Aquaporins (AQPs) play a pivotal role in the cellular transport of water and many other small solutes, influencing many physiological and developmental processes in plants. In the present study, extensive bioinformatics analysis of AQPs was performed in Aquilegia coerulea L., a model species belonging to basal eudicots, with a particular focus on understanding the AQPs role in the developing petal nectar spur. A total of 29 AQPs were identified in Aquilegia, and their phylogenetic analysis performed with previously reported AQPs from rice, poplar and Arabidopsis depicted five distinct subfamilies of AQPs. Interestingly, comparative analysis revealed the loss of an uncharacterized intrinsic protein II (XIP-II) group in Aquilegia. The absence of the entire XIP subfamily has been reported in several previous studies, however, the loss of a single clade within the XIP family has not been characterized. Furthermore, protein structure analysis of AQPs was performed to understand pore diversity, which is helpful for the prediction of solute specificity. Similarly, an AQP AqcNIP2-1 was identified in Aquilegia, predicted as a silicon influx transporter based on the presence of features such as the G-S-G-R aromatic arginine selectivity filter, the spacing between asparagine-proline-alanine (NPA) motifs and pore morphology. RNA-seq analysis showed a high expression of tonoplast intrinsic proteins (TIPs) and plasma membrane intrinsic proteins (PIPs) in the developing petal spur. The results presented here will be helpful in understanding the AQP evolution in Aquilegia and their expression regulation, particularly during floral development.

Galactolipids are essential for compensating for the loss of phospholipids by “membrane lipid remodeling” in plants under phosphorus (P) deficiency. Monogalactosyl diacylglycerol (MGDG) synthases catalyze the synthesis of MGDG which is further converted into digalactosyl diacylglycerol (DGDG), later replacing phospholipids in the extraplastidial membranes. However, the roles of these enzymes are not well explored in rice. In this study, the rice MGDG synthase gene, OsMGD3 was identified and functionally characterized. We showed that plant phosphate (Pi) status and transcription factor OsPHR2 are involved in the transcriptional regulation of OsMGD3. CRISPR/Cas9 knockout (KO) and overexpression (OE) lines of OsMGD3 were generated to explore its potential role in rice adaptation to Pi deficiency. Compared to WT, OsMGD3 KO lines displayed a reduction while OE lines showed an enhanced, Pi acquisition and utilization. Further, OsMGD3 showed a predominant role in roots, altering lateral root growth. Our comprehensive lipidomic analysis revealed the role of OsMGD3 in membrane lipid remodeling in addition to a role in regulating diacylglycerol and phosphatidic acid levels that affected the expression of Pi transporters. Our study highlights the role of OsMGD3 in affecting both internal P utilization and P acquisition in rice.