Isolation and chromosomal localization of the human glutathione peroxidase gene

We have isolated cDNA clones for the gene, termed GPX1, encoding the major human selenoprotein, glutathione peroxidase. Sequence analysis confirmed previous findings that the unusual amino acid seleno-cysteine is encoded by the opal terminator codon UGA. Southern blot analysis of human genomic DNA with the GPX1 cDNA showed that restriction endonucleases without sites in the probe sequence produced three hybridizing bands at standard stringency, diminishing to one strongly and one weakly hybridizing band at high stringency. In situ hybridization localized the human GPX1 gene to a single site on chromosome 3, at region 3q11-13.1. Thus, three genomic sites bear sequence homology to the GPX1 cDNA, and the one most homologous maps to 3q11-13.1.     

An unusual intronic mutation in the CYBB gene giving rise to chronic granulomatous disease

The most common, X-linked, form of chronic granulomatous disease (CGD) is caused by mutations in the CYBB gene located at Xp21.1. The product of this gene is the large subunit of flavocytochrome b558, gp91phox, which forms the catalytic core of the antimicrobial superoxide-generating enzyme, NADPH oxidase. In the overwhelming majority of cases, mutations are family-specific and occur in the exonic regions of the gene, or more rarely at the intron/exon borders. Alternatively, they are large (often multi-gene) deletions. In addition, four mutations have been found in the promoter region. In contrast, very few intronic mutations have been reported. Here we describe an intronic mutation that causes X-linked CGD. A single nucleotide substitution in the middle of intron V creates a novel 5' splice site and results in multiple abnormal mRNA products.     

p47(phox) PX domain of NADPH oxidase targets cell membrane via moesin-mediated association with the actin cytoskeleton

Activation of phagocytic NADPH oxidase requires association of its cytosolic subunits with the membrane-bound flavocytochrome. Extensive phosphorylation of the p47(phox) subunit of NADPH oxidase marks the initiation of this activation process. The p47(phox) subunit then translocates to the plasma membrane, bringing the p67(phox) subunit to cytochrome b558 to form the active NADPH oxidase complex. However, the detailed mechanism for targeting the p47(phox) subunit to the cell membrane during activation still remains unclear. Here, we show that the p47(phox) PX domain is responsible for translocating the p47(phox) subunit to the plasma membrane for subsequent activation of NADPH oxidase. We also demonstrate that translocation of the p47(phox) PX domain to the plasma membrane is not due to interactions with phospholipids but rather to association with the actin cytoskeleton. This association is mediated by direct interaction between the p47(phox) PX domain and moesin.     

Ribosomal Protein Genes RPS10 and RPS26 Are Commonly Mutated in Diamond-Blackfan Anemia

Diamond-Blackfan anemia (DBA), an inherited bone marrow failure syndrome characterized by anemia that usually presents before the first birthday or in early childhood, is associated with birth defects and an increased risk of cancer. Although anemia is the most prominent feature of DBA, the disease is also characterized by growth retardation and congenital malformations, in particular craniofacial, upper limb, heart, and urinary system defects that are present in ∼30%–50% of patients. DBA has been associated with mutations in seven ribosomal protein (RP) genes, RPS19, RPS24, RPS17, RPL35A, RPL5, RPL11, and RPS7, in about 43% of patients. To continue our large-scale screen of RP genes in a DBA population, we sequenced 35 ribosomal protein genes, RPL15, RPL24, RPL29, RPL32, RPL34, RPL9, RPL37, RPS14, RPS23, RPL10A, RPS10, RPS12, RPS18, RPL30, RPS20, RPL12, RPL7A, RPS6, RPL27A, RPLP2, RPS25, RPS3, RPL41, RPL6, RPLP0, RPS26, RPL21, RPL36AL, RPS29, RPL4, RPLP1, RPL13, RPS15A, RPS2, and RPL38, in our DBA patient cohort of 117 probands. We identified three distinct mutations of RPS10 in five probands and nine distinct mutations of RPS26 in 12 probands. Pre-rRNA analysis in lymphoblastoid cells from patients bearing mutations in RPS10 and RPS26 showed elevated levels of 18S-E pre-rRNA. This accumulation is consistent with the phenotype observed in HeLa cells after knockdown of RPS10 or RPS26 expression with siRNAs, which indicates that mutations in the RPS10 and RPS26 genes in DBA patients affect the function of the proteins in rRNA processing.     

Biological controls upon the physical taphonomy of exceptionally preserved salamanders from the Miocene of Rubielos de Mora,northeast Spain

McNamara, M.E., Orr, P.J., Manzocchi, T., Alcalá, L., Anadón, P. & Peñalver, E. 2011: Biological controls upon the physical taphonomy of exceptionally preserved salamanders from the Miocene of Rubielos de Mora, northeast Spain. Lethaia, Vol. 45, pp. 210–226. The middle Miocene Rubielos de Mora Konservat‐Lagerstätte of northeast Spain is hosted within profundal, finely laminated, lacustrine mudstones. The diverse biota includes abundant salamanders. Most individuals died during separate episodes and sank rapidly postmortem. Specimens are typically preserved in dorso‐ventral aspect, the most hydrodynamically stable orientation. The near‐cylindrical morphology of the body, however, allowed some carcasses to settle in or subsequently re‐orientate into, lateral orientations. Loss of skeletal elements (i.e. reduced completeness) reflects their location within the body and followed a distal to proximal trend. Two stages are identified: initial loss of a small number of phalanges, followed by loss of more proximal limb bones plus additional phalanges. Disarticulation is more complex: it occurred via several mechanisms (notably, abdominal rupture and re‐orientation of part of the body and limbs during decay) and shows no consistent pattern among specimens. The physical taphonomy of the salamanders is controlled predominantly by intrinsic biological factors, i.e. the geometry of the body and of individual skeletal elements, the orientation, inherent strength and location of specific joints and the extent to which soft tissues, particularly the skin, persist during decay. These biological factors probably control patterns of physical taphonomy of other fossil tetrapods with a similar skeletal configuration. □Articulation, completeness, Konservat‐Lagerstätten, orientation, quantitative taphonomy, salamanders.     

Systems analysis of primary Sjögren's syndrome pathogenesis in salivary glands identifies shared pathways in human and a mouse model

Bone tissue has an exceptional quality to regenerate to native tissue in response to injury. However, the fracture repair process requires mechanical stability or a viable biological microenvironment or both to ensure successful healing to native tissue. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. Preclinical and clinical studies using biologic agents like recombinant bone morphogenetic proteins have demonstrated an efficacy similar or better than that of autologous bone graft in acute fracture healing. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications.