Model system to study classical nuclear export signals

Signal-mediated protein transport through the nuclear pore complex is of considerable interest in the field of molecular pharmaceutics. Nuclear localization signals can be used to target genes/antisense delivery systems to the nucleus Studying nuclear export is useful in enhancing the expression and the efficiency of action, of these therapeutic agents. The mechanism of nuclear import has been well studied and most of the proteins participating in this mechanism have been identified. The subject of nuclear export is still in the initial stages and there is a considerable amount of uncertainty in this area. Two main export receptors identified so far are Exportin 1 (Crm1) and Calreticulin. Crm1 recognizes certain leucine-rich amino acid sequences in the proteins it exports called classical nuclear export signals. This paper describes a model system to study, identify, and establish these classical nuclear export signals using green fluorescent protein (GFP). Two putative export signals in the human progesterone receptor (PR) and the strongest nuclear export signal known (from mitogen activated protein kinase kinase [MAPKK]) were studied using this model system

Pesquisa de estrógeno e progesterona no epitélio das pregas vocais de mulheres por imunohistoquímica Immunohistochemical searching for estrogen and progesterone receptors in women vocal fold epithelia

A laringe é extremamente sensível a mudanças endocrinológicas. A maioria das alterações da mucosa das pregas vocais é causada por modificações do conteúdo líquido das pregas vocais e das suas modificações epiteliais. O estrógeno e a progesterona interferem e modificam esse conteúdo líquido das pregas vocais. O objetivo deste trabalho é verificar a presença de receptores de estrógeno e progesterona no epitélio das pregas vocais de mulheres. MATERIAL E MÉTODO: Estudo de casos prospectivos. Foram realizados exames de imunohistoquímica para receptores de estrógeno e progesterona em 19 espécimes de epitélio de pregas vocais que não apresentavam quaisquer indícios de afecção, inclusive inflamatória. Foram descartados casos de pacientes com idade superior a 40 anos e inferior a 15 anos. RESULTADOS: Foram encontrados receptores para progesterona em 18 de 19 pacientes. Os receptores de progesterona estão localizados tanto no núcleo quanto no citoplasma e principalmente na camada basal. Não houve nenhum caso de receptores de estrógeno nas pregas vocais. CONCLUSÃO: O epitélio das pregas vocais apresenta receptores para progesterona, tanto no citoplasma quanto no núcleo. Não foram encontrados receptores para estrógeno no epitélio das pregas vocais estudadas.<br>Larynx is extremely sensitive to endocrinologic changes. Most vocal fold mucosa alterations are caused by changes in vocal fold liquid content and its epithelial changes. Estrogen and progesterone interfere and change this liquid content in the vocal folds. Our goal with the present paper is to study the presence of estrogen and progesterone receptors on vocal fold epithelium in 19 vocal fold epithelium specimens that did not present any indication of disease, especially inflammatory disease. We discarded those cases of patients above 40 years of age and those below 15. RESULTS: we found progesterone receptors in 18 of the 19 patients. The progesterone receptors are located both in the nucleus and the cytoplasm of cells, and mainly in the basal layer. There was no report of estrogen receptors present in the vocal folds. CONCLUSION: Vocal fold epithelium bears progesterone receptors, in the cytoplasm and in the nucleus. We did not find estrogen receptors in the epithelia of the vocal folds investigated