FGF‐2 mRNA and its antisense message are expressed in a developmentally specific manner in the chick limb bud and mesonephros

Abstract

FGF-2 protein is present in the ectoderm and mesoderm of the developing chick limb bud. Its importance has been shown by the ability of ectopically applied FGF-2 to replace the apical ectodermal ridge, allowing complete outgrowth and subsequent pattern formation of the limb bud. The first goal of this study was to determine whether FGF-2 mRNA was present in the same ectodermal and mesodermal regions of the chick embryo as FGF-2 protein. FGF-2 also has an antisense message that is convergently transcribed from the opposite DNA strand (Kimelman and Kirschner 119891 Cell 59687496; Volk et al.[1989] EMBO J. 82983-2988). The second goal was to demonstrate the expression and distribution of the antisense message. Using RNAse protection assays we detected a full length protected fragment that corresponds to chick embryo FGF-2 mRNA, and a partially protected fragment that corresponds to the antisense message. We used in situ hybridization to show that FGF-2 mRNA was present in the ectoderm and subjacent mesoderm of the chick wing bud. FGF-2 mRNA was also present in body ectoderm and undifferentiated mesoderm throughout the embryo, and in muscle cells, dorsal neural tube, and mesonephros. In situ hybridization also revealed evidence for the presence of the natural antisense message in the embryo in most, but not all, of the same regions as the FGF-2 mRNA. FGF-2 mRNA and its antisense message colocalized in undifferentiated limb mesoderm; however, antisense message was not detected in differentiated muscle or cartilage. It is important to note that FGF-2 mRNA was always present in the mesonephros but that the antisense message was never observed in the mesonephros, thereby providing an internal control for non-specific signal. Although little is known about its function, Kimelman and Kirschner ([19891 Cell 5 9 687-696) proposed that the antisense message may increase turnover of FGF-2 mRNA. When we compared the in situ hybridization data of both mRNAs with levels of FGF-2 protein (Savage et al.

Multiple S Gene Family Members Including Natural Antisense Transcripts Are Differentially Expressed during Development of Maize Flowers

“…Of particular interest in the developing male sexual tissues, the sense and antisense transcripts showed complementary expression patterns, with antisense RNAs decreasing in abundance as the anther matures, whereas sense S-like transcripts were accumulating at the highest level in mature pollen. The apparent reciprocal relationship between the abundance of sense and absence of antisense S transcripts in mature pollen supports the possibility of a regulatory role for the antisense transcript in control of male reproductive development, as described previously in animals for several developmental processes (51,52,68,78,83).…”

FGF signaling pathways in endochondral and intramembranous bone development and human genetic disease

“…However, in the absence of FGF9 there are no apparent defects in skeletal development (Colvin et al 2001a,b). Similarly,Fgf2,Fgf5,Fgf6, and Fgf7 are expressed in loose mesenchyme outside the condensation (Haub and Goldfarb 1991;deLapeyriere et al 1993;Mason et al 1994;Finch et al 1995;Savage and Fallon 1995). However, mice lacking these FGFs have no apparent defects in skeletal development (Hebert et al 1994;Guo et al 1996;Fiore et al 1997).…”

Fibroblast growth factors 2 and 4 stimulate migration of mouse embryonic limb myogenic cells

“…In this study, we have concentrated on members of the FGF family (FGF-2 and FGF-4), because, during migration, limb myogenic cells express FREK, which is the FGF receptor (Marcelle et al, 1995). FGF-2, FGF-4, and FGF-8 genes are expressed very early on in limb development by the apical ectodermal ridge (AER), and it is now believed that these isoforms are likely candidates for the signaling molecules responsible for many of the inductive properties of the AER (Niswander and Martin, 1992;Crossley and Martin, 1995;Savage and Fallon, 1995). These cytokines can functionally replace the AER by providing the signals necessary to stimulate both the outgrowth and the patterning of the limb.…”

“…FGF-2 and FGF-4 are also involved in maintaining ZPA signaling and sonic hedgehog expression Li et al, 1996). Aside from the AER, FGF-2 is also present in the early limb bud associate within the ectoderm, the peripheral mesenchyme, and migrating myogenic cells (Dono and Zeller, 1994;Savage and Fallon, 1995).…”