ABSTRACT
Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine to phosphatidic acid and choline. A variety of signal molecules such as hormones, neurotransmitters, extracellular matrix molecules, and growth factors are known to induce the activation of PLD in a wide range of cell types. Hence PLD is implicated in a broad spectrum of physio-logical processes and diseases, including mitogenesis, cell differentiation, metabolic regulation, secretion, neural and cardiac stimulation, inflammation, oncogenesis, and diabetes. The signal-dependent activation of PLD has been observed in a variety of brain and neural-derived cells. In this paper, human chromosomal locations and developmental neural expression patterns in rat of PLD1 and PLD2 were investigated with fluorescent in situ hybridization (FISH) and in situ hybridization histochemistry, respectively. The PLD1 was assigned to human chromosome 3q26 and expressed most strikingly in selected ventricular neural cells lining spinal cord and brain during neuronal differentiation and migration period. The PLD2 was assigned to human chromosome 17p13.1 and expressed in differentiating ventricular neural cells and multiple regions of the postnatal rat brain.
Subject(s)
Animals , Humans , Humans , Rats , Brain , Carcinogenesis , Cell Differentiation , Choline , Chromosomes, Human , Extracellular Matrix , Hydrolysis , In Situ Hybridization , In Situ Hybridization, Fluorescence , Inflammation , Intercellular Signaling Peptides and Proteins , Neurons , Neurotransmitter Agents , Phosphatidic Acids , Phosphatidylcholines , Phospholipase D , Phospholipases , Spinal CordABSTRACT
To understand the early cellular differentiation of neurons, we studied the differentiation of ventral spinal cord (VSC) neurons in culture. Immunofluorescence techniques with myelin associated protein 2 (MAP2) and phosphorylated neurofilament heavy chain were used with phase contrast microscopy. VSC neurons were best grown and differentiated on the coverslips coated with polyethylenimine or poly-L-Lysine. During 3 days of culture, VSC neurons changed from a round cell with no neurites to multipolar neurons with an axon and dendrites. The differentiating VSC neurons could be classified into 4 types based on the shape and length of processes. The process with axonal character, that is MAP2 negative and phosphorylated neurofilament positive, was first identified at the tip of dendritic process when one or more processes grew out. Our results suggest that the formation of an axon in VSC neurons may follow the formation of dendrites.