Different levels of the homeodomain protein cut regulate distinct dendrite branching patterns of Drosophila multidendritic neurons

Functionally similar neurons can share common dendrite morphology, but how different neurons are directed into similar forms is not understood. Here, we show in embryonic and larval development that the level of Cut immunoreactivity in individual dendritic arborization (da) sensory neurons correlates with distinct patterns of terminal dendrites: high Cut in neurons with extensive unbranched terminal protrusions (dendritic spikes), medium levels in neurons with expansive and complex arbors, and low or nondetectable Cut in neurons with simple dendrites. Loss of Cut reduced dendrite growth and class-specific terminal branching, whereas overexpression of Cut or a mammalian homolog in lower-level neurons resulted in transformations toward the branch morphology of high-Cut neurons. Thus, different levels of a homeoprotein can regulate distinct patterns of dendrite branching.     

Inactivation of Numb and Numblike in embryonic dorsal forebrain impairs neurogenesis and disrupts cortical morphogenesis

Numb and Numblike, conserved homologs of Drosophila Numb, have been implicated in cortical neurogenesis; however, analysis of their involvement in later stages of cortical development has been hampered by early lethality of double mutants in previous studies. Using Emx1(IREScre) to induce more restricted inactivation of Numb in the dorsal forebrain of numblike null mice beginning at E9.5, we have generated viable double mutants that displayed striking brain defects. It was thus possible to examine neurogenesis during the later peak phase (E12.5-E16.5). Loss of Numb and Numblike in dorsal forebrain resulted in neural progenitor hyperproliferation, delayed cell cycle exit, impaired neuronal differentiation, and concomitant defects in cortical morphogenesis. These findings reveal novel and essential function of Numb and Numblike during the peak period of cortical neurogenesis. Further, these double mutant mice provide an unprecedented viable animal model for severe brain malformations due to defects in neural progenitor cells.     

Relative importance of osmotic-stress and ion-specific effects on ABA-mediated inhibition of leaf expansion growth in Phaseolus vulgaris

The osmotic and ion-specific components of salt-induced inhibition of leaf expansion growth were investigated in beans grown from 12 h to several days in either NaCl-containing solution cultures, an isosmotic concentrated macronutrient solution, or a vermiculite–compost mixture with low Na⁺ but high Cl^– availability. Inhibition of leaf expansion and leaf ABA increase was more intense in the NaCl than in the isosmotic macronutrient treatment. Root Na⁺ was highly correlated to inhibition of leaf expansion and leaf or xylem sap ABA. When Na⁺ was sequestered in soil, salinized plants showed no reduction in leaf expansion or ABA increase, regardless of the presence of high leaf Cl^– concentrations. Stomatal conductance exhibited an exponential relationship with the reciprocal value of xylem sap ABA. Our results indicate that an ion-specific effect caused by Na⁺ in roots may account for an ABA-mediated reponse of both stomatal closure and leaf expansion inhibition.     

RAB-10-Dependent Membrane Transport Is Required for Dendrite Arborization

Formation of elaborately branched dendrites is necessary for the proper input and connectivity of many sensory neurons. Previous studies have revealed that dendritic growth relies heavily on ER-to-Golgi transport, Golgi outposts and endocytic recycling. How new membrane and associated cargo is delivered from the secretory and endosomal compartments to sites of active dendritic growth, however, remains unknown. Using a candidate-based genetic screen in C. elegans, we have identified the small GTPase RAB-10 as a key regulator of membrane trafficking during dendrite morphogenesis. Loss of rab-10 severely reduced proximal dendritic arborization in the multi-dendritic PVD neuron. RAB-10 acts cell-autonomously in the PVD neuron and localizes to the Golgi and early endosomes. Loss of function mutations of the exocyst complex components exoc-8 and sec-8, which regulate tethering, docking and fusion of transport vesicles at the plasma membrane, also caused proximal dendritic arborization defects and led to the accumulation of intracellular RAB-10 vesicles. In rab-10 and exoc-8 mutants, the trans-membrane proteins DMA-1 and HPO-30, which promote PVD dendrite stabilization and branching, no longer localized strongly to the proximal dendritic membranes and instead were sequestered within intracellular vesicles. Together these results suggest a crucial role for the Rab10 GTPase and the exocyst complex in controlling membrane transport from the secretory and/or endosomal compartments that is required for dendritic growth.     

Conditional Survival in de novo Metastatic Urothelial Carcinoma

Background

Second-line therapy is frequently utilized for metastatic urothelial carcinoma, but there are limited data to guide this approach. While an assessment of overall survival based on registry data may not capture the impact of second- and third-line therapies on clinical outcome, this may be reflected in relative conditional survival (RCS).

Methods

Patients with stage IV urothelial carcinoma diagnosed from 1990–2010 were identified from the Surveillance, Epidemiology and End Results (SEER) dataset. The association of clinicopathologic variables with disease specific survival (DSS) was explored through univariate and multivariate analyses. DSS in subgroups divided by time period (1990–2000 v 2001–2010) was compared using the Kaplan-Meier method and log-rank test. One-year RCS at annual landmarks up to 5 years was compared in subgroups divided by time period.

Results

Of 261,987 patients diagnosed with urothelial carcinoma from 1990–2010, 3,110 patients met criteria for the current analysis. Characteristics of patients diagnosed between 1990 and 2000 (n = 810) and 2001 to 2010 (n = 2,300) were similar and there was no significant difference in DSS between the two groups. On multivariate analysis, older age (age ≥ 80) was associated with shorter DSS (HR 1.79, 95%CI 1.48–2.15), but no association was found between time period of diagnosis and outcome. One-year RCS improved substantially through successive annual landmarks up to 5 years, but no differences were seen in subgroups divided by time of diagnosis.

Conclusions

No difference in RCS was observed amongst patients with stage IV urothelial carcinoma diagnosed from 1990–2000 and 2001–2010. A lack of difference in RCS (more so than cumulative DSS) may reflect a lack of progress in salvage therapies for the disease.     

Hepatopancreas but not ovary is the site of vitellogenin synthesis in female fresh water crab, Oziothelphusa senex senex

The objective of the present study was to explore the site of synthesis of vitellogenin (Vtg) in fresh water edible crab, Oziothelphusa senex senex. Vtg cDNA fragments were isolated from the hepatopancreas of female crabs using RT-PCR method, and the deduced amino acid sequence of O. senex senex showed more than 60% identity with other brachyuran Vtg sequences. RT-PCR analysis showed that Vtg mRNA can be detected only in hepatopancreas of female Oziothelphusa but not in other tissues including eyestalks, Y-organs, mandibular organs, thoracic ganglion, hypodermis and ovary. Antibodies were raised against vitellin purified from the ovary of O. senex senex. Immunoprecipitation analysis revealed the presence of Vtg in the hepatopancreas of vitellogenic stage I females and in the hemolymph, hepatopancreas and ovary extracts from vitellogenic stage II females but absent in hemolymph and hepatopancreas extract of males. These results suggest that Vtg is synthesized only in hepatopancreas but not in the ovaries of O. senex senex. In addition, Vtg synthesized in hepatopancreas is transported to ovary through hemolymph.     

Spatiotemporal Expression of tmie in the Inner Ear of Rats during Postnatal Development

The circling (cir/cir) mouse is a murine model for human nonsyndromic deafness DFNB6. Transmembrane inner ear (tmie) is the causative gene and its mutation through deletion of a 40-kilobase genomic region including tmie leads to deafness. The function of Tmie is unknown. To better understand the function of Tmie, we focused on the spatiotemporal expression of tmie in the rat cochlea by using a Tmie-specific antibody. Results showed that tmie expression was prominent in early postnatal rat cochleas in the stereocilia bundles of hair cells. The Tmie signal spread from the stereocilia to the hair cell body region and on to organ of Corti cells. No Tmie signal was observed in cell nuclei; Tmie was localized to the cytoplasm. Because Tmie is predicted to have 1 or 2 transmembrane domains, we postulate that it is localized to membrane-based organelles or the plasma membrane. Our results imply that Tmie exists in the cytoplasm and may have a key role in the maturation and structure of stereocilia bundles in developing hair cells. After hair cell maturation, Tmie is thought to be involved in the maintenance of organ of Corti cells.Circling is often observed in mouse and rat deafness mutants and is commonly suggested to be a consequence of inner ear defects that impair vestibular systems.^3,12,14 The circling (cir/cir) mouse is a murine model for human nonsyndromic deafness DFNB6; these mice have abnormal circling behavior, suggesting a balance disorder, and profound deafness.^6,7 The most notable pathologic phenotypes of circling mice are the almost completely degenerated cochlea and remarkably reduced cellularity in spiral ganglion neurons. The causative gene for circling is transmembrane inner ear (tmie), with a 40-kilobase genomic deletion including tmie.¹ tmie is also the causative gene of the spinner (sr/sr) mouse, which has phenotypes similar to circling mice, although the mutation patterns are different.⁸ Spinner mice also show circling behavior, hearing loss, imbalance, and swimming inability. In addition, spinner mice have 2 mutations in the tmie gene: the 40-kb genomic deletion including tmie and a point mutation that leads to a truncated protein.⁸In humans, 7 different homozygous recessive mutations in TMIE currently are known to exist in affected members of consanguineous families segregating severe-to-profound prelingual deafness, consistent with linkage to DFNB6.^9,10 Although the functions of murine Tmie and human TMIE are unknown, this protein appears to be important for normal hearing and vestibular function.In a previous study, we produced transgenic mice overexpressing tmie that resulted in phenotypic rescue of circling.¹¹ Normal expression of transgenic tmie induced phenotypic rescue in circling homozygous mutants, although some mice did not show amelioration of abnormal behavior, hearing ability, or tissue morphology in the inner ear. Therefore the Tmie protein is required for normal inner ear function in mouse.¹¹To better understand the function of Tmie, we focused on the spatiotemporal expression of tmie. Knowing when, where, and to what extent this protein is produced in the developing inner ear will provide important clues to protein function. In adult mouse and rat, tmie is expressed in various tissues.^2,13 Whether Tmie plays an important role in those tissues is uncertain, because circling mice that lack the entire tmie gene have no noteworthy problems in any tissues except those of the inner ear systems.⁶In this study, we were interested in the postnatal stages before and after the onset of hearing (around postnatal day [P] 12) in rats; therefore, the postnatal period P0 to19 was studied. Although all the cells that form the mature cochlea are present at birth, important conformational changes occur during this period, including the formation of the tunnel of Corti and the establishment or retraction of neuronal connections. The expression pattern of tmie in the developing inner ear during early postnatal development has not been investigated previously. Here we document our use of a Tmie-specific antibody to elucidate the spatial and temporal expression of tmie in the rat inner ear during postnatal development.