The fragile X mental retardation protein (FMRP), the functional absence of which causes
fragile X syndrome, is an RNA-binding protein that has been implicated in the regulation of
local protein synthesis at the synapse. The mechanism of FMRP's interaction with its target
mRNAs, however, has remained controversial. In one model, it has been proposed that BC1
RNA, a small non-protein-coding RNA that localizes to synaptodendritic domains, operates
as a requisite adaptor by specifically binding to both FMRP and, via direct base-pairing, to …

To the editor: Iacoangeli et al.(1) set out to reexamine our model that FMRP and the
noncoding RNA BC1 act together to bind to mRNAs (2). Basing conclusions entirely on an
inability to find this specific interaction, the authors suggest that FMRP and BC1 operate
independently. Repeated statements suggesting experimental procedures are
''replicating''those in ref. 2 imply the authors tried to rigorously reproduce our experiments.
This is patently untrue. Numerous important experimental differences easily explain the …