LIN28B, LIN28A, KISS1, and KISS1R in idiopathic central precocious puberty

Abstract Background Pubertal timing is a strongly heritable trait, but no single puberty gene has been identified. Thus, the genetic background of idiopathic central precocious puberty (ICPP) is poorly understood. Overall, the genetic modulation of pubertal onset most likely arises from the additive effect of multiple genes, but also monogenic causes of ICPP probably exist, as cases of familial ICPP have been reported. Mutations in KISS1 and KISSR, coding for kisspeptin and its receptor, involved in GnRH secretion and puberty onset, have been suggested causative for monogenic ICPP. Variation in LIN28B was associated with timing of puberty in genome-wide association (GWA) studies. LIN28B is a human ortholog of the gene that controls, through microRNAs, developmental timing in C. elegans. In addition, Lin28a transgenic mice manifest the puberty phenotypes identified in the human GWAS. Thus, both LIN28B and LIN28A may have a role in pubertal development and are good candidate genes for monogenic ICPP. Methods Thirty girls with ICPP were included in the study. ICPP was defined by pubertal onset before 8 yrs of age, and a pubertal LH response to GnRH testing. The coding regions of LIN28B, LIN28A, KISS1, and KISS1R were sequenced. The missense change in LIN28B was also screened in 132 control subjects. Results No rare variants were detected in KISS1 or KISS1R in the 30 subjects with ICPP. In LIN28B, one missense change, His199Arg, was found in one subject with ICPP. However, this variant was also detected in one of the 132 controls. No variation in LIN28A was found. Conclusions We did not find any evidence that mutations in LIN28B or LIN28A would underlie ICPP. In addition, we confirmed that mutations in KISS1 and KISS1R are not a common cause for ICPP.

Glycoprotein Interactions in the Assembly of Hantaviruses

Hantaviruses are one of the five genera of the vector-borne virus family Bunyaviridae. While other members of the family are transmitted via arthropods, hantaviruses are carried and transmitted by rodents and insectivores. Occasional transmission to humans occurs via inhalation of aerosolized rodent excreta. When transmitted to man hantaviruses cause hemorrhagic fever with renal syndrome (HFRS, in Eurasia, mortality ~10%) and hantavirus cardiopulmonary syndrome (HCPS, in the Americas, mortality ~40%). The single-stranded, negative-sense RNA genome of hantaviruses is in segments S, M and L that respectively encode for nucleocapsid (N), glycoproteins Gn and Gc, and RNA-dependent RNA-polymerase (RdRp or L protein). The genome segments, encapsidated by N protein to form ribonucleoprotein (RNP), are enclosed inside a lipid envelope decorated by spikes formed of Gn and Gc. The focus of this study was to understand the mechanisms and interactions through which the virion is formed and maintained. We observed that when extracted from virions both Gn and Gc favor homo- over hetero-oligomerization. The minimal glycoprotein complexes extracted from virion by detergent were observed, by using ultracentrifugation and gel filtration, to be tetrameric Gn and homodimeric Gc. These results led us to suggest a model where tetrameric Gn complexes are interconnected through homodimeric Gc units to form the grid-like surface architecture described for hantaviruses. This model was found to correlate with the three-dimensional (3D) reconstruction of virion surface created using cryo-electron tomography (cryo-ET). The 3D-density map showed the spike complex formed of Gn and Gc to be 10 nm high and to display a four-fold symmetry with dimensions of 15 nm times 15 nm. This unique square-shaped complex on a roughly round virion creates a hitch for the assembly, since a sphere cannot be broken into rectangles. Thus additional interactions are likely required for the virion assembly. In cryo-ET we observed that the RNP makes occasional contacts to the viral membrane, suggesting an interaction between the spike and RNP. We were able to demonstrate this interaction using various techniques, and showed that both Gn and Gc contribute to the interaction. This led us to suggest that in addition to the interactions between Gn and Gc, also the interaction between spike and RNP is required for assembly. We found galectin-3 binding protein (referred to as 90K) to co-purify with the virions and showed an interaction between 90K and the virion. Analysis of plasma samples taken from patients hospitalized for Puumala virus infection showed increased concentrations of 90K in the acute phase and the increased 90K level was found to correlate with several parameters that reflect the severity of acute HFRS. The results of these studies confirmed, but also challenged some of the dogmas on the structure and assembly of hantaviruses. We confirmed that Gn and RNP do interact, as long assumed. On the other hand we demonstrated that the glycoproteins Gn and Gc exist as homo-oligomers or appear in large hetero-oligomeric complexes, rather than form primarily heterodimers as was previously assumed. This work provided new insight into the structure and assembly of hantaviruses.

Cohésion modale et subordination : Le conditionnel et le jussif finnois au miroir de la valeur sémantique et discursive du subjonctif français

Modal cohesion and subordination. The Finnish conditional and jussive moods in comparison to the French subjunctive This study examines verb moods in subordinate clauses in French and Finnish. The first part of the analysis deals with the syntax and semantics of the French subjunctive, mood occurring mostly in subordinate positions. The second part investigates Finnish verb moods. Although subordinate positions in Finnish grammar have no special finite verb form, certain uses of Finnish verb moods have been compared to those of subjunctives and conjunctives in other languages. The present study focuses on the subordinate uses of the Finnish conditional and jussive (i.e. the third person singular and plural of the imperative mood). The third part of the analysis discusses the functions of subordinate moods in contexts beyond complex sentences. The data used for the analysis include 1834 complex sentences gathered from newspapers, online discussion groups and blog texts, as well as audio-recorded interviews and conversations. The data thus consist of both written and oral texts as well as standard and non-standard variants. The analysis shows that the French subjunctive codes theoretical modality. The subjunctive does not determine the temporal and modal meaning of the event, but displays the event as virtual. In a complex sentence, the main clause determines the temporal and modal space within which the event coded by the subjunctive clause is interpreted. The subjunctive explicitly indicates that the space constructed in the main clause extends its scope over the subordinate clause. The subjunctive can therefore serve as a means for creating modal cohesion in the discourse. The Finnish conditional shares the function of making explicit the modal link between the components of a complex construction with the French subjunctive, but the two moods differ in their semantics. The conditional codes future time and can therefore occur only in non-factual or counterfactual contexts, whereas the event expressed by French subjunctive clauses can also be interpreted as realized. Such is the case when, for instance, generic and habitual meaning is involved. The Finnish jussive mood is used in a relatively limited number of subordinate clause types, but in these contexts its modal meaning is strikingly close to that of the French subjunctive. The permissive meaning, typical of the jussive in main clause positions, is modified in complex sentences so that it entails inter-clausal relation, namely concession. Like the French subjunctive, the jussive codes theoretical modal meaning with no implication of the truth value of the proposition. Finally, the analysis shows that verb moods mark modal cohesion, not only on the syntagmatic level (namely in complexe sentences), but also on the paradigmatic axis of discourse in order to create semantic links over entire segments of talk. In this study, the subjunctive thus appears, not as an empty category without function, as it is sometimes described, but as an open form that conveys the temporal and modal meanings emerging from the context.