Fgf-R3 is expressed in a subset of chicken spinal motorneurons

The expression pattern of the fibroblast growth factor receptor Fgf-R1, R2 and R3 genes was studied in the chicken spinal cord using in situ hybridiza tion (ISH). Unlike Fgf-R1 which is widely expressed in motoneurons, Fgf-R3 is expressed in a subset of motoneurons in the medial subdivision of the me dian motor column (MMCm) that also express Islet-1 and Lim-3. The motoneuro n identity of the labelled cells was confirmed by double ISH and by single cell RT-PCR. Interestingly, E3.5 spinal cord motoneurons do not express Fgf -R3, suggesting the expression of Fgf-R3 in motoneurons begins with axonal growth. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.