In the Absence of Frazzled Over-Expression of Abelson Tyrosine Kinase Disrupts Commissure Formation and Causes Axons to Leave the Embryonic CNS

BACKGROUND: In the Drosophila embryonic nerve cord, the formation of commissures require both the chemoattractive Netrin receptor Frazzled (Fra) and the Abelson (Abl) cytoplasmic tyrosine kinase. Abl binds to the cytoplasmic domain of Fra and loss-of-function mutations in abl enhance fra-dependent commissural defects. To further test Abl's role in attractive signaling, we over-expressed Abl in Fra mutants anticipating rescue of commissures. METHODOLOGY/PRINCIPAL FINDINGS: The Gal4-UAS system was used to pan-neurally over-express Abl in homozygous fra embryos. Surprisingly, this led to a significant decrease in both posterior and anterior commissure formation and induced some commissural and longitudinal axons to project beyond the CNS/PNS border. Re-expressing wild-type Fra, or Fra mutants with a P-motif deleted, revert both commissural and exiting phenotypes, indicating that Fra is required but not a specific P-motif. This is supported by S2 cell experiments demonstrating that Abl binds to Fra independent of any specific P-motif and that Fra continues to be phosphorylated when individual P-motifs are removed. Decreasing midline repulsion by reducing Robo signaling had no effect on the Abl phenotype and the phenotypes still occur in a Netrin mutant. Pan-neural over-expression of activated Rac or Cdc42 in a fra mutant also induced a significant loss in commissures, but axons did not exit the CNS. CONCLUSION/SIGNIFICANCE: Taken together, these data suggest that Fra activity is required to correctly regulate Abl-dependent cytoskeletal dynamics underlying commissure formation. In the absence of Fra, increased Abl activity appears to be incorrectly utilized downstream of other guidance receptors resulting in a loss of commissures and the abnormal projections of some axons beyond the CNS/PNS border

From the Editor's Desk

From the Editor's Desk&nbsp

A Cultural Longing for Jesus Christ Vampire Hunter

A Cultural Longing for Jesus Christ Vampire Hunte

From the Editor’s Desk

From the Editor’s Des

Oxidative Degradation of Fingerprints

Fingerprints deposited at crime scenes are useful evidence for identifying people who have been there. Fingerprints can remain on surfaces for a long time and there is presently no method to determine age without destroying the print. Here, we explore the quantifiable aging effects of time on fingerprint oil and sweat. Using both standard synthetic sweat and synthesized eccrine oil mixture, Raman spectroscopy was used to measure oxidation and degradation of prints over time. The hypothesis is that oxidative degradation occurs at the unsaturated sites of the oils and causes quantifiable changes in the composition. This should lead to a method for determining fingerprint age. We present Raman spectra of samples at time intervals showing the changes that occur. Raman offers the best method for this analysis because field portable instruments are commercially available making non-destructive field measurements possible

Da sacralização da economia à sacralização da política: a teologia da libertação como uma versão católica de rejeição intramundana do mundo

A principal components analysis of the ten scales of the Worry Questionnaire revealed the existence of major worry factors or domains of social evaluation and physical threat, and these factors were confirmed in a subsequent item analysis. Those high in trait anxiety had much higher scores on the Worry Questionnaire than those low in trait anxiety, especially on those scales relating to social evaluation. Scores on the Marlowe-Crowne Social Desirability Scale were negatively related to worry frequency. However, groups of low-anxious and repressed individuals formed on the basis of their trait anxiety and social desirability scores did not differ in worry. It was concluded that worry, especially in the social evaluation domain, is of fundamental importance to trait anxiety