Cloning of expressed sequence tags (ESTs) representing putative epileptogenesis-related genes and the localization of their expression in the normal brain.

ABSTRACT

The goal of this study was to clone and sequence selected expressed sequence tags (ESTs) which mRNA is upregulated in a rat model of epilepsy based on our previous work [17] and to determine the localization of their mRNA expression in the normal brain. Six ESTs that had not been assigned to any gene at the time of the inception of our experiments were chosen for analysis. Radioactive in situ hybridization revealed that the expression of four transcripts (AA955087, AA875438, AA899079, AA819660) was clearly localized to hippocampal neurons and was also detected in the cortex. Two transcripts, AA819523 and AA819766, displayed a uniform expression pattern. 5'RACE cloning and sequencing allowed for the annotation of five ESTs to known or predicted genes sorting nexin-2 (SNX2), tweety homolog 1 (Ttyh1), selenoprotein T (SelT), transmembrane protein 204 (Tmem204) and methyl-CpG binding domain protein 3 (Mbd3). According to the results of our combined non-radioactive in situ hybridization and immunohistochemistry with cell-specific markers, mRNA coding for Ttyh1, Tmem204 and Mbd3 was expressed in neurons. The potential role of the studied genes in normal brain or in brain pathology remains elusive and requires further study because little is known about these genes in general.