ABSTRACT
The formation of axon tracts in nervous system histogenesis is the result of selective axon fasciculation and specific growth cone guidance in embryonic development. One group of proteins implicated in neurite outgrowth, fasciculation, and guidance is the neural members of the Ig superfamily (IgSF). In an attempt to identify and characterize new proteins of this superfamily in the developing nervous system, we used a PCR-based strategy with degenerated primers that represent conserved sequences around the characteristic cysteine residues of Ig-like domains. Using this approach, we identified a novel neural IgSF member, termed neurotractin. This GPI-linked cell surface glycoprotein is composed of three Ig-like domains and belongs to the IgLON subgroup of neural IgSF members. It is expressed in two isoforms with apparent molecular masses of 50 and 37 kD, termed L-form and S-form, respectively. Monoclonal antibodies were used to analyze its biochemical features and histological distribution. Neurotractin is restricted to subsets of developing commissural and longitudinal axon tracts in the chick central nervous system. Recombinant neurotractin promotes neurite outgrowth of telencephalic neurons and interacts with the IgSF members CEPU-1 (KD = 3 x 10(-8) M) and LAMP. Our data suggest that neurotractin participates in the regulation of neurite outgrowth in the developing brain.
Subject(s)
Avian Proteins , Cell Adhesion Molecules, Neuronal/metabolism , Immunoglobulins/metabolism , Membrane Glycoproteins/metabolism , Membrane Proteins/metabolism , Nerve Tissue Proteins/metabolism , Neurites/metabolism , Amino Acid Sequence , Animals , Axons/metabolism , Base Sequence , Brain/metabolism , CHO Cells , COS Cells , Central Nervous System , Chick Embryo , Chickens , Cricetinae , DNA, Complementary , GPI-Linked Proteins , Immunoglobulin G , Membrane Proteins/genetics , Molecular Sequence Data , Nerve Tissue Proteins/genetics , Neurons , TelencephalonABSTRACT
Plate-like crystals of adrenodoxin reductase from bovine adrenocortical mitochondria were obtained in a new modification. The crystals belong to the monoclinic space group C2 with cell parameters a = 85.94 A, b = 62.64 A, c = 128.55 A and beta = 99.8 degrees. There are two molecules in the asymmetric unit. The crystals diffract to better than 3.0 A resolution at 4 degrees C.
Subject(s)
Ferredoxin-NADP Reductase/ultrastructure , Adrenal Glands/enzymology , Animals , Cattle , Crystallography, X-Ray , Ferredoxin-NADP Reductase/chemistry , Mass Spectrometry , Molecular WeightABSTRACT
Crystals of adrenodoxin from bovine adrenocortical mitochondria were obtained by the hanging-drop vapor diffusion technique. The crystals belong to a hexagonal crystal lattice with cell parameters 172.50 A and 183.49 A. There are 12 molecules in the asymmetric unit. The crystals diffract to beyond 4.0 A resolution.
