G-TRACE: rapid Gal4-based cell lineage analysis in Drosophila.

We combined Gal4-UAS and the FLP recombinase-FRT and fluorescent reporters to generate cell clones that provide spatial, temporal and genetic information about the origins of individual cells in Drosophila melanogaster. We named this combination the Gal4 technique for real-time and clonal expression (G-TRACE). The approach should allow for screening and the identification of real-time and lineage-traced expression patterns on a genomic scale.

Genomewide clonal analysis of lethal mutations in the Drosophila melanogaster eye: comparison of the X chromosome and autosomes.

Using a large consortium of undergraduate students in an organized program at the University of California, Los Angeles (UCLA), we have undertaken a functional genomic screen in the Drosophila eye. In addition to the educational value of discovery-based learning, this article presents the first comprehensive genomewide analysis of essential genes involved in eye development. The data reveal the surprising result that the X chromosome has almost twice the frequency of essential genes involved in eye development as that found on the autosomes.

An efficient genetic screen in Drosophila to identify nuclear-encoded genes with mitochondrial function.

We conducted a screen for glossy-eye flies that fail to incorporate BrdU in the third larval instar eye disc but exhibit normal neuronal differentiation and isolated 23 complementation groups of mutants. These same phenotypes were previously seen in mutants for cytochrome c oxidase subunit Va. We have molecularly characterized six complementation groups and, surprisingly, each encodes a mitochondrial protein. Therefore, we believe our screen to be an efficient method for identifying genes with mitochondrial function.

Dissection and mounting of Drosophila pupal eye discs.

The Drosophila melanogaster eye disc is a powerful system that can be used to study many different biological processes. It contains approximately 800 separate eye units, termed ommatidia. Each ommatidium contains eight neuronal photoreceptors that develop from undifferentiated cells following the passage of the morphogenetic furrow in the third larval instar. Following the sequential differentiation of the photoreceptors, non-neuronal cells develop, including cone and pigment cells, along with mechanosensory bristle cells. Final differentiation processes, including the structured arrangement of all the ommatidial cell types, programmed cell death of undifferentiated cell types and rhodopsin expression, occurs through the pupal phase. This technique focuses on manipulating the pupal eye disc, providing insight and instruction on how to dissect the eye disc during the pupal phase, which is inherently more difficult to perform than the commonly dissected third instar eye disc. This technique also provides details on immunostaining to allow the visualization of various proteins and other cell components.

Chronic kidney disease is associated with increased coronary artery atherosclerosis as revealed by multidetector computed tomographic angiography.

Chronic kidney disease (CKD) is an independent risk factor for cardiovascular events. We evaluated whether multidetector computed tomographic angiography (MDCTA) revealed a link between pre-dialysis CKD and coronary artery atherosclerosis. We retrospectively analyzed 549 patients who underwent MDCTA. Patients were divided into 3 groups: normal glomerular filtration rate (GFR) (GFR>90 mL/min/1.73 m2 body surface area), mild CKD (>60GFR≤90 mL/min/1.73 m2), and moderate CKD (>30GFR≤60 mL/min/1.73 m2). Normality testing was performed to determine if continuous variables were modeled in Gaussian distribution before analysis of variance was applied. The χ2 test was used to compare GFR subgroups. Multiple linear regression was used to detect associations of total plaque score (TPS), segment involvement score (SIS), and segment stenosis score (SSS) with GFR. A model adjusted for covariates was applied. Patients with mild CKD had a mean TPS 2.3 points higher than those with a normal GFR (P=0.002); patients with moderate CKD had a mean TPS 5.9 points higher than the referent (P<0.001). Patients with mild CKD had a mean SIS 1.1 points higher than those with a normal GFR (P=0.002); patients with moderate CKD had a mean SIS 2.4 points higher than the referent (P<0.001). Patients with mild CKD had a mean SSS 1.4 points higher than those with a normal GFR (P=0.004); patients with moderate CKD had a mean SSS 4.2 points higher than the referent (P<0.001). The use of MDCTA showed that mild and moderate pre-dialysis CKD are independent risk factors for coronary artery atherosclerosis.

Mild and moderate pre-dialysis chronic kidney disease is associated with increased coronary artery calcium.

BACKGROUND: It is increasingly evident that patients with chronic kidney disease (CKD) are more likely to die from heart disease than kidney failure. This study evaluated whether pre- dialysis CKD is an independent risk factor for coronary artery calcium (CAC). METHODS: A total of 544 consecutive patients who underwent CAC scoring were analyzed. Eleven patients requiring hemodialysis were excluded. Patients were divided into three groups: normal glomerular filtration rate (GFR) (GFR > 90 mL/min/1.73 m²), mild CKD (90 ≥ GFR > 60 mL/min/1.73 m²), and moderate CKD (60 ≥ GFR > 30 mL/min/1.73 m²). Continuous and categorical variables were compared using analysis of variance and the χ² statistic. A multiple logistic regression model was used for detecting the association between total CAC score and GFR. An unadjusted model was used, followed by a second model adjusted for covariates known to be related to CAC. Another multivariable binary logistic model predicting the presence of CAC (>10) was performed and odds of incidence of CAC (>10) were calculated among the three GFR subgroups. RESULTS: After adjustment for covariates, patients with mild CKD had mean CAC scores 175 points higher than those with the referent normal GFR (P = 0.048), while those with moderate CKD had mean CAC scores 693 points higher than the referent (P < 0.001). After adjustment for covariates, patients with mild CKD were found to be 2.2 times more likely (95% confidence interval 1.3-3.7, P = 0.004) and patients with moderate CKD were 6.4 times more likely (95% confidence interval 2.9-14.3, P < 0.001) to have incident CAC compared with the group with normal GFR. CONCLUSION: Mild and moderate pre-dialysis CKD are independent risk factors for increased mean and incident CAC.