FGF4 regulates blood and muscle specification in Xenopus laevis.

Background Information: FGF (fibroblast growth factor) signalling is known to be required for many aspects of mesoderm formation and patterning during Xenopus development and has been implicated in regulating genes required for the specification of both blood and skeletal muscle lineages.

Results: In the present study, we have specifically knocked down the expression of FGF4 using AMO (antisense morpholino oligonucleotide)-mediated inhibition and demonstrate that FGF4 acts in the dorsal marginal zone to restrict blood development and promote the development of skeletal muscle. In addition, we used a drug inhibitor of FGF signalling and an inducible form of FGFR1 (FGF receptor 1) to identify a period of competence during late blastula and gastrula stages when FGF signalling acts to regulate blood versus muscle specification.

Atherin: a newly identified, lesion-specific, LDL-binding protein in human atherosclerosis.

Prolonged retention of LDL in focal, atherosclerosis-prone areas of arteries is a primary event in atherogenesis. To determine whether unrecognized LDL-binding proteins participate in this process, we generated a cDNA expression library from deendothelialized rabbit aorta, a model for early atherosclerosis that shows striking focal LDL retention in healing lesions. Library screening identified a previously unknown, highly conserved, 56kDa LDL-binding protein that we call atherin.