Expression of neurofilament L-promoter green-fluorescent protein constructs in immortalized Schwann cell-neuron coculture.
The neurofilament L/68 protein (NF-L/68) gene is expressed in the immature Schwann cell phenotype but suppressed after myelin-formation. We have investigated conditions which regulate the activity of the NF-L/68 promoter in green fluorescent protein reporter constructs expressed in the immortal rat Schwann cell strain SCL4.1/F7 in coculture with neurons. Constructs expressed in a plasmid vector containing both the full-length promoter and the 3' proximal 107 bp sequence which includes the cyclic AMP response element (CRE), were active in SCL4.1/F7 cells, but were suppressed as the cells underwent spontaneous growth-arrest. Interaction of SCL4.1/F7 with axons accelerated downregulation of expression from both constructs, however expression of the full-length promoter continued in some cells until the onset of myelin-formation. Expression of the NFL/68 construct recommenced when demyelination was induced in culture by exposure to human sera from patients with paraproteinemic gammopathy. We have demonstrated a method to study the regulation of gene expression patterns in single Schwann cells interacting with neurons and shown that different promoter regions may be controlled by axon-related and -unrelated factors.
Haynes
L W
LW
School of Biological Sciences, The University of Bristol, UK. l.haynes@bris.ac.uk
Schmitz
S
S
Clegg
J C
JC
Fooks
A R
AR
D000818:Animals; D002450:Cell Communication / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods; D002461:Cell Line, Transformed / Q000737:chemistry / Q000502:physiology; D015870:Gene Expression / Q000502:physiology; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D006801:Humans; D007202:Indicators and Reagents; D008164:Luminescent Proteins / Q000235:genetics*; D009186:Myelin Sheath / Q000502:physiology; D016900:Neurofilament Proteins / Q000235:genetics*; D009474:Neurons / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D011401:Promoter Regions, Genetic; D051381:Rats; D012583:Schwann Cells / Q000737:chemistry / Q000166:cytology / Q000502:physiology*
D007202:Indicators and Reagents; D008164:Luminescent Proteins; D016900:Neurofilament Proteins; C044882:neurofilament protein L; D049452:Green Fluorescent Proteins