Expression of the Fanconi anemia group A gene (Fanca) during mouse embryogenesis

About 80% of all cases of Fanconi anemia (FA) can be accounted for by compl ementation groups A and C. To understand the relationship between these gro ups, we analyzed the expression pattern of the mouse FA group-A gene (Fanca ) during embryogenesis and compared it with the known pattern of the group- C gene (Fanca). Northern analysis of RNA from mouse embryos at embryonic da ys 7, 11, 15, and 17 showed a predominant 4.5 kb band in all stages. By in situ hybridization, Fanca transcripts were found in the whisker follicles, teeth, brain, retina, kidney, liver, and limbs. There was also stage-specif ic variation in Fanca expression, particularly within the developing whiske rs and the brain. Some tissues known to express Fancc (eg, gut) failed to s how Fanca expression. These observations show that (1) Fanca is under both tissue- and stage-specific regulation in several tissues; (2) the expressio n pattern of Fanca is consistent with the phenotype of the human disease; a nd (3) Fanca expression is not necessarily coupled to that of Fancc. The pr esence of distinct tissue targets for FA genes suggests that some of the va riability in the clinical phenotype can be attributed to the complementatio n group assignment. (C) 1999 by The American Society of Hematology.