The THO complex is required for nucleolar integrity in Drosophila spermatocytes

Sungjin Moon, Bongki Cho, Su Hong Min, Daekee Lee, Yun Doo Chung

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


The THO complex is a conserved multisubunit protein complex that functions in the formation of export-competent messenger ribonucleoprotein (mRNP). Although the complex has been studied extensively at the single-cell level, its exact role at the multicellular organism level has been poorly understood. Here, we isolated a novel Drosophila male sterile mutant, garmcho (garm). Positional cloning indicated that garm encodes a subunit of the Drosophila THO complex, THOC5. Flies lacking THOC5 showed a meiotic arrest phenotype with severe nucleolar disruption in primary spermatocytes. A functional GFP-tagged fusion protein, THOC5-GFP, revealed a unique pattern of THOC5 localization near the nucleolus. The nucleolar distribution of a testisspecific TATA binding protein (TBP)-associated factor (tTAF), SA, which is required for the expression of genes responsible for sperm differentiation, was severely disrupted in mutant testes lacking THOC5. But THOC5 appeared to be largely dispensable for the expression and nuclear export of either tTAF target mRNAs or tTAF-independent mRNAs. Taken together, our study suggests that the Drosophila THO complex is necessary for proper spermatogenesis by contribution to the establishment or maintenance of nucleolar integrity rather than by nuclear mRNA export in spermatocytes.

Original languageEnglish
Pages (from-to)3835-3845
Number of pages11
Issue number17
StatePublished - 1 Sep 2011


  • Drosophila
  • Meiotic arrest
  • Nucleolus
  • Spermatogenesis
  • THO complex


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