Identification of novel trkA variants with deletions in leucine-rich motifs of the extracellular domain

The peripheral expression of trkA encoding for NGF receptor was investigate d by RNase protection assay. A thymus-specific protected fragment was ident ified. Using 5' rapid amplification of cDNA ends, three different trkA frag ments were characterized. The longer fragment corresponded to the classical trkA L3 transcripts while the two shorter fragments lacked sequences encod ing for leucine-rich motifs of the extracellular domain of TrkA, similarly to the trkB L1 and L0 variants. RT-PCR analysis of adult rat tissues showed the expression of trkA L1 transcripts in the thymus, testis, lung and kidn ey but not in the central nervous system. Their combined expression with tr kA L3 transcripts suggests that specific peripheral TrkA oligomers may modu late NGF binding and function in non-neuronal cells. (C) 2000 Elsevier Scie nce B.V. All rights reserved.