Novel FADS3 Alternative Transcripts Generated By Alternative Splicing

Abstract

ObjectiveWe report the first multiple transcript variants of a fatty acid desaturase (FADS), FADS3, generated by alternative splicing, and tissue and cell specific expression.BackgroundFatty acid desaturases are enzymes that catalyze the introduction of cis double bonds at specific positions in a fatty acid chain. FADS1, FADS2 and FADS3 are thought to be the key desaturase enzymes involved in the biosynthesis of long chain polyunsaturated fatty acids. Functions of FADS1 and FADS2 are known, however, the function of FADS3 gene product remains unknown.ProcedureThe protein coding region of baboon FADS3 and FADS3 alternative transcripts (AT), were generated from primers synthesized using human and monkey FADS3 cDNA sequences. To analyze the expression levels of each AT, primers bridging the deleted parts of the exons were designed, tested by RT‐PCR and the products were confirmed by sequencing. The expression was analyzed in baboon tissues and in differentiated and undifferentiated human SK‐N‐SH neuroblastoma cells (NB).ResultsAided by ORF Finder, we identified eight AT for FADS3 with 1.34 kb (classical splicing), 1.14 (AT1), 0.77 (AT2), 1.25 (AT3), 0.51 (AT4), 0.74 (AT6), and 1.11 (AT7). In addition we identified an AT of 0.51 kb (AT5) length that has termination codon within the intron 8‐9. FADS3 AT expression is tissue dependent in 12 baboon tissues. NB cells showed reciprocal increases and decreases in expression.ConclusionThis is the first finding of AT of FADS genes. The FADS3 AT are expressed in many tissues and showed changes in response to neuronal cell differentiation.Support: NIH grant GM071534