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Cloning and expression of SEZ-6, a brain-specific and seizure-related cDNA
K Shimizu-Nishikawa1, K Kajiwara, M Kimura
1Department of Physiology, Kanagawa Dental College, Japan.
Abstract:
To clarify the molecular mechanism of neuronal bursting activity of seizures, we have constructed a cDNA library from mouse cerebrum cortex-derived cells treated with pentylentetrazole (PTZ), one of the convulsant drugs. Using a differential screening technique, several cDNA clones whose expressions change with PTZ-treatment were obtained. Among these clones, SEZ-6 was characterized by increased expression with PTZ. Detailed northern analysis showed that expression of SEZ-6 was limited to the brain and increased by the administration of PTZ not only in in vitro cultured cells but also in vivo. Analysis of SEZ-6 cDNA revealed multiple motifs, including typical signal sequence, threonine-rich domain, five copies of short consensus repeats (SCRs) or sushi domain (complement C3b/C4b binding site), two repeated sequences which were partially similar to the CUB domain or complement C1r/s-like repeat, one transmembrane domain and a short cytoplasmic segment in the C-terminal region. Although many proteins with multiple SCRs or CUB domains other than complement-related proteins have been found, this is the first report about a brain-specific cDNA which encodes membrane protein with both SCRs and CUB domain-like segments. Based on these findings, it is evident that SEZ-6 encodes a novel type of protein which may be related to seizure.
Insights
Researchers identified SEZ-6, a novel brain-specific protein, whose expression increases with pentylentetrazole (PTZ) treatment. This discovery sheds light on the molecular mechanisms underlying neuronal bursting activity and seizures.
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- Neuronal bursting activity is a hallmark of seizures.
- The molecular mechanisms driving seizure activity require further elucidation.
Purpose of the Study:
- To identify novel genes involved in seizure mechanisms.
- To characterize the function and expression of PTZ-induced genes.
Main Methods:
- Construction of a mouse cerebrum cortex cDNA library from PTZ-treated cells.
- Differential screening to identify differentially expressed cDNA clones.
- Northern blot analysis to confirm expression patterns.
- Sequence analysis of identified cDNA clones.
Main Results:
- Identified SEZ-6 cDNA with increased expression upon PTZ treatment.
- Demonstrated brain-specific expression of SEZ-6, upregulated both in vitro and in vivo.
- Characterized SEZ-6 as a novel membrane protein containing signal sequence, threonine-rich domain, SCRs, CUB domain-like repeats, and a transmembrane domain.
Conclusions:
- SEZ-6 represents a novel brain-specific membrane protein.
- Its expression pattern suggests a potential role in seizure pathophysiology.
- This finding offers new insights into the molecular basis of neuronal excitability and seizure generation.