Identification of two novel splicing variants of murine NTE-related esterase

NTE-related esterase (NRE) is an insulin-regulated lysophospholipase with homology to neuropathy target esterase (NTE), which plays a role in energy metabolism. Here, we reported two alternative splicing variants of the murine NRE (mNRE) gene, termed mNREV1 and mNREV2. Genomic organization analysis indicated that 5' splice site of mNRE intron 33 was changed in both mNREV1 and mNREV2, and mNRE exon 21 was deleted in mNREV2. mNREV1 had the same protein domains with mNRE, while mNREV2 lacked the patatin domain in the C-terminal catalytic region. Green fluorescent protein-mNREV1 or mNREV2 fusion proteins localized to the endoplasmic reticulum. mNREV1 and mNRE exhibited equal hydrolytic activity to the substrate phenyl valerate, whereas mNREV2 did not have any catalytic activity. The expression profiles of mNRE and its splicing isoforms in white adipose tissue, cardiac muscle, skeletal muscle, and testis tissues were further analyzed by real time quantitative-PCR in fed and fasted states, which indicated that the major isoform of mNRE mRNA generated switched from mNREV2 to mNREV1 during fasting. Thus there was a nutritional regulation of mNRE expression at the mRNA levels via alternative splicing.