Drosophila Fragile X Protein controls cellular proliferation by regulating cbl levels in the ovary

Andrew M. Epstein, Christopher R. Bauer, Aaron Ho, Giovanni Bosco, Daniela C. Zarnescu

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


FMRP is an RNA binding protein linked to the most common form of inherited mental retardation, Fragile X syndrome (FraX). In addition to severe cognitive deficits, FraX etiology includes postpubescent macroorchidism, which is thought to result from overproliferation. Using a Drosophila FraX model, we show that FMRP controls germline proliferation during oogenesis. dFmr1 null ovaries contain egg chambers with both fewer and supranumerary germ cells. The mutant germaria contain a significantly increased number of cyclin E and PhosphoHistone H3 positive cells, suggesting that loss of FMRP leads to defects in cell cycle progression. BrdU incorporation and flow cytometry data suggest that, in addition to proliferation, germline endoreplication and ploidy are also affected by the loss of FMRP during ovary development. Here we report that FMRP controls the levels of cbl mRNA in the ovary and that reducing cbl gene dosage by half rescues the dFmr1 oogenesis phenotypes. These data support a model whereby FMRP controls germline proliferation by regulating the expression of cbl in the developing ovary.

Original languageEnglish (US)
Pages (from-to)83-92
Number of pages10
JournalDevelopmental biology
Issue number1
StatePublished - Jun 1 2009


  • Drosophila
  • Fragile X protein
  • Oogenesis
  • Proliferation
  • cbl

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology


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