Isolation and characterization of a Jerky and JRK/JH8 like gene, tigger transposable element derived 7, TIGD7.

Abstract

Epilepsy is a common seizure disease of nearly 1–2% people during their lives. It is known that some forms of epilepsy, such as idiopathic generalized epilepsy (IGE) and childhood absence epilepsy (ACE) (McNamara, 1999; Morita et al., 1999), are related to genetic factors. But their molecular mechanisms remain unknown. In 1995, Toth et al. found a novel gene whose knockout in mice could lead to whole body jerking, generalized colonic seizures, and epileptic brain activity (Toth et al., 1995). Accordingly, the gene was named Jerky. The mouse Jerky gene is located on chromosome 15, encoding a 60 kDa protein of 509 amino acids. Jerky mRNA was detectable in various other mouse tissues by reverse transcription-PCR. Some experiments showed that the Jerky protein is brain specific and is highly expressed in mouse neurons. It was also reported that the protein can bind mRNAs with high affinity (Liu et al., 2002). In 1998, the human counterpart of the mouse Jerky gene, JRK/JH8 (Jerky/the Jerky homologue of the human on chromosome 8), was isolated and mapped. The results of RT-PCR showed it is expressed ubiquitously (Morita et al., 1998). Polymorphism analysis of this gene was performed in patients with idiopathic generalized epilepsy. The results showed that a mutation in the JRK/JH8 ORF may have some relation to this disease (Morita et al., 1999). Jerky and JRK/JH8 show high similarity with several members of the tigger subfamily. In 1996, some DNA transposon fossils related to the Drosophila