Mutation in the Scyl1 gene encoding amino-terminal kinase-like protein causes a recessive form of spinocerebellar neurodegeneration

Here, we show that the murine neurodegenerative disease mdf (autosomal recessive mouse mutant 'muscle deficient') is caused by a loss-of-function mutation in Scyl1, disrupting the expression of N-terminal kinase-like protein, an evolutionarily conserved putative component of the nucleocytoplasmic transport machinery. Scyl1 is prominently expressed in neurons, and enriched at central nervous system synapses and neuromuscular junctions. We show that the pathology of mdf comprises cerebellar atrophy, Purkinje cell loss and optic nerve atrophy, and therefore defines a new animal model for neurodegenerative diseases with cerebellar involvement in humans.     

A view from the NIH bridge: perspectives of a program officer

This essay is written from my perspective as a program officer for research and training activities at the National Institute of General Medical Sciences (NIGMS) for almost 27 yr. It gives a bird's-eye view of the job of a program officer, which includes providing advice to applicants and grantees, making funding recommendations, overseeing grantees' progress, facilitating scientific opportunities in specific areas of program responsibility, and shaping NIGMS and National Institutes of Health (NIH) policy. I have highlighted the numerous rewards of serving as a program officer, as well as some of the difficulties. For those who may be considering a position as an NIH program officer now or in the future, I've also described the qualities and qualifications that are important for such a career choice. Finally, this essay addresses some of the challenges for the NIH and the research community in the years ahead as we simultaneously face exciting scientific opportunities and tighter budgets.     

A common founder for amyotrophic lateral sclerosis type 8 (ALS8) in the Brazilian population

The P56S mutation in the VAPB gene causes ALS8. Eight families, comprising more than 1,500 individuals of whom about 200 are affected, are now known to carry this mutation. Seven are of Portuguese–Brazilian ancestry and one of African–Brazilian ancestry. Haplotype analysis shows a common founder for all families regardless of ancestry, with a founding event 23 generations ago (95% CI 13–39), consistent with the Portuguese colonization of Brazil.Agnes L. Nishimura, Ammar Al-Chalabi contributed equally to this work     

Equal proportions of affected cells in muscle and blood of a mosaic carrier of facioscapulohumeral muscular dystrophy

Autosomal dominant facioscapulohumeral muscular dystrophy (FSHD) is associated with contractions of D4Z4 repeat on 4q35. It displays a remarkable inter- and intra-familial clinical variability ranging from severe phenotype to asymptomatic carriers. Mosaicism for the contracted FSHD-sized allele is a recurrent finding, but only DNA from lymphocytes had been studied. It is currently not known if mosaicism is unequally distributed between different tissues and if muscle is relatively spared for the presence of the disease allele in mosaic asymptomatic carriers of a disease allele. Here we compare DNA extracted from peripheral blood lymphocytes (PBL), fibroblasts and muscle from a mosaic asymptomatic female carrier and mother of a FSHD patient. PFGE analysis showed a complex allelic segregation: two independent mitotic rearrangement episodes occurred, resulting in mosaicism for a contracted D4Z4 repeat on 4q35 in the mother and mosaicism for an expanded D4Z4 repeat on 10q26 in the affected daughter. The results show that the proportion of mosaicism in PBL and muscle were comparable, while in fibroblasts there was some variation in the mosaicism, which might be caused by culturing artefacts. This finding supports the hypothesis that a mitotic contraction of D4Z4 is an early embryonic event and indicates that the degree of mosaicism in PBL is representative for that of muscle.     

Denervation Supersensitivity of the Rat Pineal to Norepinephrine-Stimulated [3H]Inositide Turnover Revealed by Lithium and a Convenient Procedure

A convenient procedure for the assay of myo-[2-3H(N)]inositol ([3H]inositol) metabolites in cells or small amounts of tissue was developed. The procedure is a composite of modifications of published methods. After preincubation with [3H]inositol, rat pineal glands were disrupted in an acidified organic solvent mixture. Lipids were separated from the hydrophilic products and precursor using Sephadex G-25 columns and further analyzed by TLC. Hydrophilic products were further analyzed by anion-exchange column chromatography using Dowex AG1-X8 (formate form). In the presence of lithium, increases in inositol phosphates consequent to stimulation of the glands by norepinephrine were apparent within 10 min. The response in denervated glands was considerably greater than in intact pineals.     

Photographic measurement of pleural surface motion during lung oscillation

The regional pleural surface expansion of an excised dog lung was measured during high-frequency ventilation (HFV) using synchronized stroboscopic photography to stop lung motion at 20 evenly spaced intervals over a respiratory cycle during ventilation at 1 Hz with a volume of 100 ml, 15 Hz with 100 ml, or 30 Hz with 50 ml. The lungs were also photographed during quasi-static deflation. The pleural surface was marked with ink dots to form 84 approximately square figures. The side lengths and areas of each of the 84 "squares" were measured for each frame of each photo sequence. At 1 Hz and during the quasi-static deflation the lung ventilated nearly synchronously, although minor nonuniformities were noted on both small and large length scales. At 15 and 30 Hz, the lung expanded asynchronously and nonuniformly, with a 78% increase in surface expansion per 100 ml of tracheal tidal volume, as frequency was increased from 1 to 30 Hz. These nonuniformities in expansion suggest marked interregional airflow and elastic wave propagation in the parenchyma during HFV.     

FUCOSE INCORPORATION INTO GLYCOPROTEINS OF MOUSE BRAIN

—Radioactive fucose was incorporated into glycoproteins of brain in vivo. After intracerebral administration of this precursor, radioactive glycoproteins were the sole detectable product. The glycoproteins formed appeared to have a slow turnover but this was due, at least in part, to re-utilization of fucose released from degraded glycoproteins. Incorporation of fucose into glycoproteins differed from that of glucosamine, since a much smaller proportion of the radioactive fucose was incorporated into soluble glycoproteins. Fucose was rapidly incorporated into glycoproteins of nerve endings, although there was relatively little incorporation into glycoproteins associated with the soluble component of the nerve-ending fraction. As found in previous studies with glucosamine, soluble glycoproteins of nerve endings turned over relatively rapidly. Pretreatment with acetoxycycloheximide markedly inhibited incorporation of fucose into glycoproteins of brain. In contrast to the results with glucosamine, comparable inhibition was observed for fucose in all subcellular fractions of brain including the particulate and soluble components derived from the nerve-ending fraction.