Merlin; NF2 Tumor Suppressor and Regulator of Receptor Distribution/Signaling / 대한이비인후과학회지

Acoustic tumor is the most common tumor originating from cerebellopontine angle. Acoustic tumor is benign and main origin of this tumor is vestibular nerve. This tumor arises in Schwann cell (SC) and is encapsulated. Recently, the tumor is called vestibular schwannoma (VS). VS is classified to two type by epidemiology, sporadic form and neurofibromatosis type 2 (NF2). NF2 is autosomal dominant inherent disorder. This tumor is characterized bilateral VS, brain tumors such as meningioma and ependymoma, and spinal or cranial nerve schwannoma. Genetic studies suggested that NF2 is caused by abnormality or mutation of NF2 gene in chromosome 22q12. Both of them are known to develop the tumor by mutation of NF2 gene. Merlin is the cytoskeletal protein product of the NF2 tumor suppressor gene that mediates cell to cell contact information to regulate SC proliferation and survival. And merlin is highly homologous to ERM proteins. Merlin function is regulated by its conformation, adopting an inactive, growth permissive state following serine 518 (S518) phosphorylation. In NF2 patients, the precise mechanisms of developing the VS are unclear. But, the abnormalities of merlin are confirmed by many studies. And now, a lot of research about merlin function is progressing. In this study, the author would introduce about merlin (structure, function, molecular pathway, tumorigenesis and regulation) which leads to VS and molecular studies about merlin, and suggest the future direction of research.

Reproductive behavior in the annual fish Austrolebias reicherti Loureiro & García 2004 (Cyprinodontiformes: Rivulidae)

Annual fishes inhabit temporary ponds that dry out seasonally and the adaptations to survive this extreme condition include high metabolic rates and an elaborate courtship behavior which ends in the deposition of drought-resistant eggs, capable of going through diapause stages in the substrate. The pronounced sexual dimorphism that these fishes show suggests that sexual selection could play a key role in the differentiation, speciation and evolution of this diverse group of fishes. However, there is scarce information about their reproductive isolation mechanisms, including detailed analysis of courtship signals. Herein, we analyzed, qualitatively and quantitatively, the reproductive behavior of Austrolebias reicherti. The behavioral units recognized in this study correspond with the previous analysis of other species of annual fishes. The most frequent unit in males was the lateral display where specific morphological and coloration patterns are displayed to the female. The female's high relative frequency and time of quietness suggest that this unit may have an evaluation role during courtship. In addition to visual displays during courtship, males perform vibrations of the dorsal and anal fins as well as body undulations; these indicate that mechanical signals may be important for attracting females. Our results support the hypothesis of multimodal signals. The conservation of behavioral patterns in courtship displays within Austrolebias suggests that species-level recognition and the barrier to hybridization may not occur at this stage, unless quantitative differences can be identified.

Os peixes anuais habitam charcos temporários que secam sazonalmente, e as adaptações para sobreviver a estas condições extremas incluem altas taxas metabólicas e um elaborado comportamento de cortejo, que culmina com a deposição de ovos resistentes à dessecação dentro do substrato, os quais são capazes de atravessar estádios de diapausa. O pronunciado dimorfismo sexual apresentado por estes peixes indica que a seleção sexual poderia estar exercendo um papel chave na diferenciação, especiação e evolução deste grupo diverso de peixes. Entretanto, informações acerca dos mecanismos de isolamento reprodutivo, incluindo uma análise detalhada dos sinais de cortejo, são escassas. Neste artigo é analisado o comportamento reprodutivo de Austrolebias reicherti de maneira qualitativa e quantitativa. As unidades comportamentais utilizadas neste estudo correspondem àquelas incluídas em análises anteriores de outras espécies de peixes anuais. A unidade comportamental mais freqüentemente observada em machos foi a "exibição lateral", onde características espécie-específicas da morfologia e colorido são exibidas para a fêmea. A alta proporção de ocorrência (em freqüência e tempo) do comportamento de "quietude" nas fêmeas indica que o mesmo poderia desempenhar um papel avaliativo durante o cortejo. Outros sinais além dos visuais estão envolvidos no cortejo dos peixes anuais; os machos vibram as nadadeiras dorsal e anal e ondulam o corpo, o que indica que os sinais mecânicos poderiam ter influência na atração das fêmeas. Estes resultados conferem suporte à hipótese de sinais multimodais, recentemente proposta. Os movimentos de cortejo altamente conservados dentro de Austrolebias indicam que o reconhecimento específico e a barreira à hibridização poderiam não ocorrer nesta etapa, a menos que se encontrem diferenças quantitativas nestes sinais comportamentais.