Subcellular localization of Mitf in monocytic cells

Microphthalmia-associated transcription factor (Mitf) is a transcription factor that plays an important role in regulating the development of several cell lineages. The subcellular localization of Mitf is dynamic and is associated with its transcription activity. In this study, we examined factors that affect its subcellular localization in cells derived from the monocytic lineage since Mitf is present abundantly in these cells. We identified a domain encoded by Mitf exon 1B1b to be important for Mitf to commute between the cytoplasm and the nucleus. Deletion of this domain disrupts the shuttling of Mitf to the cytoplasm and results in its retention in the nucleus. M-CSF and RANKL both induce nuclear translocation of Mitf. We showed that Mitf nuclear transport is greatly influenced by ratio of M-CSF/Mitf protein expression. In addition, cell attachment to a solid surface also is needed for the nuclear transport of Mitf

Congenital Esophageal Stenosis

Congenital esophageal stenosis (CES) is a rare entity with an estimated incidence of 1:25,000–50,000 live births. Three causes for CES have been described: tracheobronchial remnant, segmental fibromuscular hypertrophy, and membranous web. CES can be associated with other anomalies such as esophageal atresia, chromosomal anomalies, cardiac anomalies, intestinal atresia, anorectal malformation, and trisomy 21. Main symptoms are dysphagia, vomiting during meals, regurgitation of undigested food, insufficient growth, and relapsing pneumonia due to aspiration and typically occur when solid foods are introduced in diet. Diagnosis of esophageal stenosis is achieved with barium esophagogram and endoscopic study, but differential diagnosis among the three forms of CES can be difficult. Endoscopic ultrasonography may help in identifying correct diagnosis of cartilaginous remnant. First-line treatment consists of esophageal dilations which lead to resolution of stenosis in most of the cases. Tracheobronchial remnants typically are unresponsive to dilations and require resection of the stenotic tract followed by end-to-end anastomosis. The most serious complication is the esophageal perforation after dilation. Despite various therapeutic options, a consistent part of patients continues to complain of dysphagia and requires a follow-up for a long time