Regulation of zygotic expression of vasa gene by maternal nanos and pumilio proteins in germline cells of drosophila melanogaster

Thesis (Ph. D. in Science)--University of Tsukuba, (A), no. 2772, 2002.3.25Includes bibliographical reference

Tre1 GPCR initiates germ cell transepithelial migration by regulating Drosophila melanogaster E-cadherin

Despite significant progress in identifying the guidance pathways that control cell migration, how a cell starts to move within an intact organism, acquires motility, and loses contact with its neighbors is poorly understood. We show that activation of the G protein–coupled receptor (GPCR) trapped in endoderm 1 (Tre1) directs the redistribution of the G protein Gβ as well as adherens junction proteins and Rho guanosine triphosphatase from the cell periphery to the lagging tail of germ cells at the onset of Drosophila melanogaster germ cell migration. Subsequently, Tre1 activity triggers germ cell dispersal and orients them toward the midgut for directed transepithelial migration. A transition toward invasive migration is also a prerequisite for metastasis formation, which often correlates with down-regulation of adhesion proteins. We show that uniform down-regulation of E-cadherin causes germ cell dispersal but is not sufficient for transepithelial migration in the absence of Tre1. Our findings therefore suggest a new mechanism for GPCR function that links cell polarity, modulation of cell adhesion, and invasion

Control of lateral migration and germ cell elimination by the Drosophila melanogaster lipid phosphate phosphatases Wunen and Wunen 2

In most organisms, primordial germ cells (PGCs) arise far from the region where somatic gonadal precursors (SGPs) are specified. Although PGCs in general originate as a single cluster of cells, the somatic parts of the gonad form on each site of the embryo. Thus, to reach the gonad, PGCs not only migrate from their site of origin but also split into two groups. Taking advantage of high-resolution real-time imaging, we show that in Drosophila melanogaster PGCs are polarized and migrate directionally toward the SGPs, avoiding the midline. Unexpectedly, neither PGC attractants synthesized in the SGPs nor known midline repellents for axon guidance were required to sort PGCs bilaterally. Repellent activity provided by wunen (wun) and wunen-2 (wun-2) expressed in the central nervous system, however, is essential in this migration process and controls PGC survival. Our results suggest that expression of wun/wun-2 repellents along the migratory paths provides faithful control over the sorting of PGCs into two gonads and eliminates PGCs left in the middle of the embryo

Transcriptional regulation of Drosophila gonad formation

The formation of the Drosophila embryonic gonad, involving the fusion of clusters of somatic gonadal precursor cells (SGPs) and their ensheathment of germ cells, provides a simple and genetically tractable model for the interplay between cells during organ formation. In a screen for mutants affecting gonad formation we identified a SGP cell autonomous role for Midline (Mid) and Longitudinals lacking (Lola). These transcriptional factors are required for multiple aspects of SGP behaviour including SGP cluster fusion, germ cell ensheathment and gonad compaction. The lola locus encodes more than 25 differentially spliced isoforms and we have identified an isoform specific requirement for lola in the gonad which is distinct from that in nervous system development. Mid and Lola work in parallel in gonad formation and surprisingly Mid overexpression in a lola background leads to additional SGPs at the expense of fat body cells. Our findings support the idea that although the transcription factors required by SGPs can ostensibly be assigned to those being required for either SGP specification or behaviour, they can also interact to impinge on both processes

Enzymatic synthesis of chiral P-stereogenic phosphonoacetates

In this data article, we describe the enzymatic kinetic resolution of a series of racemic mixed phosphonoacetates, which were successfully prepared from methyl bis(2,2,2-trifluoroethyl)phosphonoacetate (Still-Gennari reagent) by alcoholysis with σ-symmetrical secondary alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Porcine liver esterase (PLE)-catalyzed kinetic resolution of some of these racemic mixed phosphonoacetates proceeded in a highly stereoselective manner to furnish the chiral P-stereogenic phosphonoacetates (up to >99% ee)

A Hepatocellular Adenoma in a Diet-induced Obese Mouse

A hepatic nodule was noted in a C57BL/6J mouse with diet-induced obesity at 53 weeks of age. Macroscopically, a protruding yellowish white nodule was observed on the visceral surface of the left lateral lobe. Light microscopy demonstrated clear demarcation from the compressed adjacent parenchyma, with loss of the distinct lobular pattern. The proliferating cells of the lesion varied in shape and showed cellular atypia and prominent nucleoli along with vacuoles of various sizes. Some of the cells contained various-sized eosinophilic inclusion bodies in their cytoplasm, and electron microscopy revealed the presence of lipid droplets in the rough endoplasmic reticulum. Eosinophilic inclusions were observed as electron dense granular material in the rough endoplasmic reticulum, with one or a few low density central cores. A diagnosis of hepatocellular adenoma was made based on these findings

Systemic and Ocular Determinants of Choroidal Structures on Optical Coherence Tomography of Eyes with Diabetes and Diabetic Retinopathy

Knowledgeof the choroidal structures in eyes with diabetes and diabetic retinopathy (DR) should provide information on the pathogenesis of DR. A prospective study was performed to determine the systemic and ocular factors that affect the choroidal structures in eyes with diabetes. Two-hundred consecutive diabetic subjects consisted of 160 treatment-naïve patients with different stages of DR and 40 patients with proliferative DR with prior panretinal photocoagulation (PRP). All underwent blood and urine tests and enhanced depth imaging optical coherence tomography (EDI-OCT). The cross-sectional EDI-OCT images of the subfoveal choroid were binarized to measure the total choroidal area (TCA), luminal area, and stromal area. Multivariate regression analyses were performed to determine the systemic and ocular factors that were significantly correlated with the choroidal structures. The subfoveal choroidal thickness, TCA, luminal area, and stromal area were larger at more advanced stage of DR, and smaller in eyes with PRP than those without (P < 0.001). The TCA and stromal area were significantly and positively correlated with the degree of albuminuria (P = 0.034, P = 0.025, respectively). The choroidal lumen and stroma may increase as the stages of DR progress and decrease after PRP. Albuminuria may be associated with the choroidal stromal edema