Systematic documentation and analysis of human genetic variation in hemoglobinopathies using the microattribution approach

We developed a series of interrelated locus-specific databases to store all published and unpublished genetic variation related to hemoglobinopathies and thalassemia and implemented microattribution to encourage submission of unpublished observations of genetic variation to these public repositories. A total of 1,941 unique genetic variants in 37 genes, encoding globins and other erythroid proteins, are currently documented in these databases, with reciprocal attribution of microcitations to data contributors. Our project provides the first example of implementing microattribution to incentivise submission of all known genetic variation in a defined system. It has demonstrably increased the reporting of human variants, leading to a comprehensive online resource for systematically describing human genetic variation in the globin genes and other genes contributing to hemoglobinopathies and thalassemias. The principles established here will serve as a model for other systems and for the analysis of other common and/or complex human genetic diseases.     

Macrophage migration inhibitory factor stimulates AMP-activated protein kinase in the ischaemic heart

Understanding cellular response to environmental stress has broad implications for human disease. AMP-activated protein kinase (AMPK) orchestrates the regulation of energy-generating and -consuming pathways, and protects the heart against ischaemic injury and apoptosis. A role for circulating hormones such as adiponectin and leptin in the activation of AMPK has received recent attention. Whether local autocrine and paracrine factors within target organs such as the heart modulate AMPK is unknown. Here we show that macrophage migration inhibitory factor (MIF), an upstream regulator of inflammation, is released in the ischaemic heart, where it stimulates AMPK activation through CD74, promotes glucose uptake and protects the heart during ischaemia-reperfusion injury. Germline deletion of the Mif gene impairs ischaemic AMPK signalling in the mouse heart. Human fibroblasts with a low-activity MIF promoter polymorphism have diminished MIF release and AMPK activation during hypoxia. Thus, MIF modulates the activation of the cardioprotective AMPK pathway during ischaemia, functionally linking inflammation and metabolism in the heart. We anticipate that genetic variation in MIF expression may impact on the response of the human heart to ischaemia by the AMPK pathway, and that diagnostic MIF genotyping might predict risk in patients with coronary artery disease.     

Potentiation of NMDA receptor currents by arachidonic acid.

Arachidonic acid is released by phospholipase A2 when activation of N-methyl-D-aspartate (NMDA) receptors by neurotransmitter glutamate raises the calcium concentration in neurons, for example during the initiation of long-term potentiation and during brain anoxia. Here we investigate the effect of arachidonic acid on glutamate-gated ion channels by whole-cell clamping isolated cerebellar granule cells. Arachidonic acid potentiates, and makes more transient, the current through NMDA receptor channels, and slightly reduces the current through non-NMDA receptor channels. Potentiation of the NMDA receptor current results from an increase in channel open probability, with no change in open channel current. We observe potentiation even with saturating levels of agonist at the glutamate- and glycine-binding sites on these channels; it does not result from conversion of arachidonic acid to lipoxygenase or cyclooxygenase derivatives, or from activation of protein kinase C. Arachidonic acid may act by binding to a site on the NMDA receptor, or by modifying the receptor's lipid environment. Our results suggest that arachidonic acid released by activation of NMDA (or other) receptors will potentiate NMDA receptor currents, and thus amplify increases in intracellular calcium concentration caused by glutamate. This may explain why inhibition of phospholipase A2 blocks the induction of long-term potentiation.     

A high-resolution map of human chromosome 12

Our sequence-tagged site-content map of chromosome 12 is now integrated with the whole-genome fingerprinting effort. It provides accurate and nearly complete bacterial clone coverage of chromosome 12. We propose that this integrated mapping protocol serves as a model for constructing physical maps for entire genomes.     

A radiation hybrid map of the rat genome containing 5,255 markers.

A whole-genome radiation hybrid (RH) panel was used to construct a high-resolution map of the rat genome based on microsatellite and gene markers. These include 3,019 new microsatellite markers described here for the first time and 1,714 microsatellite markers with known genetic locations, allowing comparison and integration of maps from different sources. A robust RH framework map containing 1,030 positions ordered with odds of at least 1,000:1 has been defined as a tool for mapping these markers, and for future RH mapping in the rat. More than 500 genes which have been mapped in mouse and/or human were localized with respect to the rat RH framework, allowing the construction of detailed rat-mouse and rat-human comparative maps and illustrating the power of the RH approach for comparative mapping.     

Distribution records and comments on fleas in southwestern South Dakota

From October 2003 through April 2006, we collected 565 fleas incidental to a distribution survey of mammals in southwestern South Dakota. Sixty-one specimens, representing 18 species of mammals, possessed 20 species of fleas. The geographic distributions of these flea species revealed 8 new records for the Black Hills and its adjacent grasslands. Four species— Megarthroglossus divisus, Stenoponia americana, Odontopsyllus dentatus, and Amaradix euphorbi —constitute new records for South Dakota, thus increasing the state’s known flea fauna to 42 species. Hunters, trappers, and field biologists should be aware that serosurveillance during the 1990s revealed the presence of sylvatic plague and tularemia in the Black Hills area. Desde octubre de 2003 hasta abril de 2006, colectamos 565 pulgas de manera incidental durante un estudio de la distribución de mamíferos en el suroeste del estado de Dakota del Sur. Los 61 especímenes, que representaban 18 especies de mamíferos, albergaban 20 especies de pulgas. Sus distribuciones geográficas revelaron 8 nuevos registros para las Colinas Negras (Black Hills) y las praderas adyacentes. Cuatro de estas especies ( Megarthroglossus divisus, Stenoponia americana, Odontopsyllus dentatus y Amaradix euphorbi ) constituyen nuevos registros para Dakota del Sur. Esto aumenta el número de especies de pulgas conocidas del estado a 42 especies. Los cazadores, tramperos y biólogos de campo deben estar conscientes de que la vigilancia serológica durante la década de los 1990 reveló la presencia de la plaga silvática y la tularemia en el área de las Colinas Negras.     

Movement of internalized ligand-receptor complexes along a continuous endosomal reticulum

Complexes of cell-surface receptors and their ligands are commonly internalized by endocytosis and enter a prelysosomal endosomal pathway for further processing. Fluorescence microscopy and video recording of living cells to trace the passage of ligand-receptor complexes has identified the endosomal compartment as an extensive network of tubular cisternae. Endocytosed material entering this reticulum enters discrete swellings, identified as multivesicular bodies by electron microscopy, which move along the reticulum towards the pericentriolar area.     

A new A4 amyloid mRNA contains a domain homologous to serine proteinase inhibitors

The amyloid proteins isolated from neuritic plaques and the cerebrovasculature of Alzheimer's disease are self-aggregating moieties termed A4 protein and beta-protein, respectively. A putative A4 amyloid precursor (herein termed A4(695] has been characterized by analysis of a human brain complementary DNA. We report here the sequence of a closely related amyloid cDNA, A4(751), distinguished from A4(695) by the presence of a 168 base-pair (bp) sequence which adds 57 amino acids to, and removes one residue from, the predicted A4(695) protein. The peptide predicted from this insert is very similar to the Kunitz family of serine proteinase inhibitors. The two A4-specific messenger RNAs are differentially expressed: in a limited survey, A4(751) mRNA appears to be ubiquitous, whereas A4(695) mRNA has a restricted pattern of expression which includes cells from neuronal tissue. These data may have significant implications for understanding amyloid deposition in Alzheimer's disease.