Bassoon, a novel zinc-finger CAG/glutamine-repeat protein selectively localized at the active zone of presynaptic nerve terminals.

The molecular architecture of the cytomatrix of presynaptic nerve terminals is poorly understood. Here we show that Bassoon, a novel protein of >400,000 Mr, is a new component of the presynaptic cytoskeleton. The murine bassoon gene maps to chromosome 9F. A comparison with the corresponding rat cDNA identified 10 exons within its protein-coding region. The Bassoon protein is predicted to contain two double-zinc fingers, several coiled-coil domains, and a stretch of polyglutamines (24 and 11 residues in rat and mouse, respectively). In some human proteins, e.g., Huntingtin, abnormal amplification of such poly-glutamine regions causes late-onset neurodegeneration. Bassoon is highly enriched in synaptic protein preparations. In cultured hippocampal neurons, Bassoon colocalizes with the synaptic vesicle protein synaptophysin and Piccolo, a presynaptic cytomatrix component. At the ultrastructural level, Bassoon is detected in axon terminals of hippocampal neurons where it is highly concentrated in the vicinity of the active zone. Immunogold labeling of synaptosomes revealed that Bassoon is associated with material interspersed between clear synaptic vesicles, and biochemical studies suggest a tight association with cytoskeletal structures. These data indicate that Bassoon is a strong candidate to be involved in cytomatrix organization at the site of neurotransmitter release.

[Supportive amblyopia treatment by means of computer games with background stimulation; a placebo controlled pilot study of 10 days]. / Unterstützende Amblyopiebehandlung durch Computerspiele mit Hintergrundstimulation: Eine 10-tägige plazebokontrollierte Pilot-Studie.

BACKGROUND: Computer programmes for visual stimulation may give new impulses to the field of amblyopia treatment by offering an option to shift the apparative visual training into the domestic sphere. Regarding this aspect we report on a placebo controlled study on a newly developed vision training consisting of a background stimulation by a drifting sinusoidal grating combined with a foreground game aimed to maintain the attention. MATERIALS AND METHODS: Fourteen amblyopia patients aged from 6 to 13 years participated in the study. Seven were allocated to a placebo and seven to a treatment group. Both groups had to train at the computer for a period of 10 working days by two sessions of about 20 minutes daily. Whilst the placebo group played in front of a neutral background, the treatment group did this with a drifting sinusoidal grating in the background. RESULTS: The treatment condition resulted in a greater increase of visual acuity than the placebo condition. Near vision improved in the treatment group from 0.20 (SD +/- 4.51 steps) to 0.39 (SD +/- 3.06 steps), i.e. by 3.0 steps of visual acuity (SD +/- 1.8 steps), in the placebo group from 0.14 (SD +/- 6.02 steps) to 0.17 (SD +/- 5.85 steps), i.e. by 0.8 steps of visual acuity (SD +/- 1.6 steps). Far vision improved in the treatment group from 0.29 (SD +/- 2.57 steps) to 0.44 (SD +/- 3.16 steps), i.e. by 1.9 steps of visual acuity (SD +/- 1.3 steps), in the placebo group from 0.24 (SD +/- 5.20 steps) to 0.28 (SD +/- 5.51 steps), i.e. by 0.7 steps of visual acuity (SD +/- 1.1 steps). CONCLUSIONS: Stimulation with drifting sinusoidal gratings improves the visual acuity of amblyopic eyes in a specific way. The effect might be accounted for by a synergy of spatial and temporal frequency in form vs. motion channels. A preliminary hypothesis is discussed and will be the subject of ongoing research. The presented method has been developed for the treatment of "delayed" amblyopia in the elder child. It is aimed to support and complement occlusion therapy. However, the reported results obtained over 10 days should be estimated only within the context of evaluation. By no means should the results be interpreted as a renewed pledge for a short-term treatment of amblyopia.

Lack of evidence for involvement of known human retroviruses in multiple sclerosis.

The recent report by Koprowski et al. that human T-cell lymphotropic retroviruses (HTLVs) may be involved in the development of multiple sclerosis (MS) has aroused much interest. The report was based largely on immunological evidence, using enzyme-linked immunosorbent assays (ELISAs) with viral antigens or disrupted virions. We have accordingly sought confirmation by screening sera and cerebrospinal fluid (CSF) samples from MS patients against cell lines infected respectively with adult T-cell leukaemia (ATL) virus (ATLV/HTLV-I) of Japanese cells (MT-1 and MT-2 lines), our own isolate from British black patients with ATL, the MoT cell line which produce HTLV-II, and our own T-cell line containing a local isolate of acquired immune deficiency syndrome (AIDS) virus (C-LAV/HTLV-III). We have failed to find antibodies against these retroviruses in the sera or CSF. Furthermore, neither virus could be isolated from the peripheral white blood cells of two MS patients.

The presynaptic cytomatrix protein Bassoon: sequence and chromosomal localization of the human BSN gene.

Bassoon is a novel 420-kDa protein recently identified as a component of the cytoskeleton at presynaptic neurotransmitter release sites. Analysis of the rat and mouse sequences revealed a polyglutamine stretch in the C-terminal part of the protein. Since it is known for some proteins that abnormal amplification of such polyglutamine regions can cause late-onset neurodegeneration, we cloned and localized the human BASSOON gene (BSN). Phage clones spanning most of the open reading frame and the 3' untranslated region were isolated from a human genomic library and used for chromosomal localization of BSN to chromosome 3p21 by FISH. The localization was confirmed by PCR on rodent/human somatic cell hybrids; it is consistent with the localization of the murine Bsn gene at chromosome 9F. Sequencing revealed a polyglutamine stretch of only five residues in human, and PCR amplifications from 50 individuals showed no obvious length polymorphism in this region. Analysis of the primary structure of Bassoon and comparison to previous database entries provide evidence for a newly emerging protein family.