Expression of the rodent-specific alternative splice variant of tryptophanyl-tRNA synthetase in murine tissues and cells

Tryptophanyl-tRNA synthetase (TrpRS) catalyzes the aminoacylation of tRNA(Trp). mRNA of a rodent-specific alternative splice variant of TrpRS (SV-TrpRS), which results in the inclusion of an additional hexapeptide at the C-terminus of full-length TrpRS (FL-TrpRS), has been identified in murine embryonic stem (ES) cells. In the present study, we evaluated the expression of mouse TrpRS mRNA by real-time reverse transcription PCR. We show that SV-TrpRS and FL-TrpRS mRNAs are highly expressed in murine ES cells, embryo, spleen, lung, liver and uterus, and that the relative expression of SV-TrpRS compared to FL-TrpRS is significantly less in the brain. Moreover, we found that interferon-γ increases the expression of TrpRS in a mouse cell line. These results provide the first evidence for tissue-specific expression and alternative splicing of mouse TrpRS.