Transient neurites of retinal horizontal cells exhibit columnar tiling via homotypic interactions
Abstract: Sensory neurons with common functions are often nonrandomly arranged and form dendritic territories that show little overlap, or tiling. Repulsive homotypic interactions underlie such patterns in cell organization in invertebrate neurons. It is unclear how dendro-dendritic repulsive interactions can produce a nonrandom distribution of cells and their spatial territories in mammalian retinal horizontal cells, as mature horizontal cell dendrites overlap substantially. By imaging developing mouse horizontal cells, we found that these cells transiently elaborate vertical neurites that form nonoverlapping columnar territories on reaching their final laminar positions. Targeted cell ablation revealed that the vertical neurites engage in homotypic interactions that result in tiling of neighboring cells before the establishment of their dendritic fields. This developmental tiling of transient neurites correlates with the emergence of a nonrandom distribution of the cells and could represent a mechanism that organizes neighbor relationships and territories of neurons before circuit assembly.

Huckfeldt RM,

Schubert T,

Morgan JL,

Godinho L,

Di Cristo G,

Huang ZJ,

Wong RO

Nat Neurosci

  12 (1): 35 - 43 ; Jan 2009

[Abstract]

[DOI] [PDF]

Reactome knowledgebase of human biological pathways and processes
Abstract: Reactome (http://www.reactome.org) is an expert-authored, peer-reviewed knowledgebase of human reactions and pathways that functions as a data mining resource and electronic textbook. Its current release includes 2975 human proteins, 2907 reactions and 4455 literature citations. A new entity-level pathway viewer and improved search and data mining tools facilitate searching and visualizing pathway data and the analysis of user-supplied high-throughput data sets. Reactome has increased its utility to the model organism communities with improved orthology prediction methods allowing pathway inference for 22 species and through collaborations to create manually curated Reactome pathway datasets for species including Arabidopsis, Oryza sativa (rice), Drosophila and Gallus gallus (chicken). Reactome's data content and software can all be freely used and redistributed under open source terms.

Matthews L,

Gopinath G,

Gillespie M,

Caudy M,

Croft D,

de Bono B,

Garapati P,

Hemish J,

Hermjakob H,

Jassal B,

Kanapin A,

Lewis S,

Mahajan S,

May B,

Schmidt E,

Vastrik I,

Wu G,

Birney E,

Stein L,

D'Eustachio P

Nucleic Acids Res

  37 (0): D619-22; Jan 2009

[Abstract]

[DOI] [PDF]