Identification of a novel splice variant of heat shock cognate protein 70 after chronic antidepressant treatment in rat frontal cortex

In this study, we identified a novel splice variant of 70-kDa heat shock co gnate protein (HSC70), while screening differentially expressed molecules i n rat brain after chronic antidepressant treatment. This clone, named HSC49 , lacked 470 bp of nucleotides of rat HSC70. HSC49 encoded 442 amino acid r esidues with a calculated molecular mass of 48.6 kDa. DNA sequence analysis revealed that HSC49 lacked the entire Exon 7 and Exon 8 of the HSC70 gene. Chronic treatment with antidepressant, imipramine or sertraline, induced a 38.5 or 22.5% increase in mRNA levels in rat frontal cortex, respectively, when compared to controls. Western blot analysis also revealed that the pr otein expression of HSC49 was increased after antidepressant treatment. Our data suggest that HSC49 may be one of the common molecules induced after c hronic antidepressant treatment. (C) 1999 Academic Press.