Characterization of plant microRNA-encoded peptides (miPEPs) reveals molecular mechanisms from the translation to activity and specificity.

MicroRNAs (miRNAs) are transcribed as long primary transcripts (pri-miRNAs) by RNA polymerase II. Plant pri-miRNAs encode regulatory peptides called miPEPs, which specifically enhance the transcription of the pri-miRNA from which they originate. However, paradoxically, whereas miPEPs have been identified in different plant species, they are poorly conserved, raising the question of the mechanisms underlying their specificity. To address this point, we identify and re-annotate multiple Arabidopsis thaliana pri-miRNAs in order to identify ORF encoding miPEPs. The study of several identified miPEPs in different species show that non-conserved miPEPs are only active in their plant of origin, whereas conserved ones are active in different species. Finally, we find that miPEP activity relies on the presence of its own miORF, explaining both the lack of selection pressure on miPEP sequence and the ability for non-conserved peptides to play a similar role, i.e., to activate the expression of their corresponding miRNA.

Total recovery of optic nerve sheath meningioma.

We reported the case of a 43-year-old woman with a rapid progressive visual loss. The diagnosis of primary optic nerve sheath meningioma was made thanks to atypia evolution, clinical and radiological findings. The patient was treated with an intensity-modulated radiotherapy of 50.4 Gy in 28 fractions 2 months after the diagnosis. Visual acuity and visual field were completely recovered after 2 years of follow-up. No late side effects of irradiation were recorded.

Clinical and genetic evaluation in a French population presenting with primary focal dystonia.

Primary focal dystonia (PFD) is known to be a clinically and genetically heterogeneous group of movement disorders. To evaluate the frequency of familial focal dystonia in a French population presenting with PFD, we screened 197 patients (150 index cases and 47 affected family members) presenting focal primary dystonia for the GAG deletion in the DYT1 gene and analyzed linkage to the DYT6, DYT7, and DYT13 loci in those who presented a family history. Fourteen families could be recruited and, among them 47 new symptomatic individuals could be identified by clinical examination. A group of 104 patients were without family history and 46 patients (30.7%) were found to have at least one first-degree relative with dystonia. Mean age at onset was significantly later (55.4 +/- 14.0 years) in the blepharospasm group and earlier in patients with writer's cramp (35.8 +/- 14.0 years). The group of patients with family history showed a mean age at onset significantly earlier (39.2 +/- 18.0) than in patients without family history (47.4 +/- 14.4 years). Fourteen families demonstrated an autosomal mode of transmission and five families were studied further for genetic linkage analysis, but no significant linkage to one of the three loci could be observed. Our results illustrate the importance of genetic factors and the clinical heterogeneity of PFD. They indicate the existence of one or several as yet unmapped genes responsible for these diseases.

Corticobasal degeneration and Parkinson's disease assessed by HmPaO SPECT: the utility of factorial discriminant analysis.

The diagnosis of corticobasal degeneration (CBD) is difficult despite the existence of some typical clinical features. Single photon emission computerized tomography (SPECT) in CBD presents an original pattern (with asymmetric hypoperfusion in pre- and retrorolandic regions) that could facilitate the differential diagnosis of CBD relative to the other degenerative parkinsonian syndromes. The objective of our study was to compare the regional cerebral blood flow measurements studied by SPECT in both CBD and Parkinson's disease (PD) using a multivariate procedure. Twenty-one patients with probable CBD and 20 patients with probable PD underwent brain (99m)Tc HmPaO SPECT. We used factorial discriminant analysis (FDA) to study the relative fixation of 26 regions of interest (ROIs) drawn on two transverse slices, together with the asymmetry indexes of 13 pairs of ROIs. FDA performed using the full set of parameters classified all the patients correctly. In order to classify the patients more easily, a predictive score using a selection of parameters was established. The most discriminating ROIs were the temporoinsular, temporoparietal, and frontal medial regions. We believe that this semiautomatic classification may be a precious tool for reinforcing the current clinical differential diagnosis of CBD and PD.