1. J. Basu and Z. Li (1998) The Des-1 protein, required for central spindle assembly and cytokinesis, is associated with mitochondria along the meiotic spindle apparatus and with the contractile ring during male meiosis in Drosophila melanogaster. Mol Gen Genet 259(6): 664-73.
Abstract Spermatogenesis in Drosophila melanogaster serves as an excellent model system for the isolation and analysis of genes required in the control of chromosome segregation and cytokinesis. We report here the isolation and molecular characterization of a novel P-element induced allele of the des-1 gene, which leads to male sterility as a consequence of the failure of central spindle assembly in meiotic spermatocytes and the formation of aberrant meiotic end products characteristic of cytokinesis failure. We have raised affinity-purified antibodies against a Des-1 fusion protein, and localized the Des-1 protein in Drosophila spermatocytes. We show that the Des- protein is colocalized with mitochondria throughout male meiosis, becoming intimately associated with mitochondria along the spindle apparatus during anaphase and telophase, and with the Nebenkern, or mitochondrial derivative, of the meiotic end products. In addition, a significant association of Des-1 with the contractile ring is observed during anaphase and telophase of meiosis. These observations, together with the presence of six potential transmembrane domains in the Des-1 protein, raise the possibility that Des-1 may act as part of an anchoring mechanism that links membrane-bounded cellular compartments to components of the cytoskeleton. PMID: [9819060]
2. I. Iliopoulos, I. Torok and B. M. Mechler (1997) The DnaJ60 gene of Drosophila melanogaster encodes a new member of the DnaJ family of proteins. Biol Chem 378(10): 1177-81.
Abstract In eukaryotes the DnaJ homolog constitute a family of proteins with diverse functions which all appear to involve the chaperone activity of Hsp70. Here, we report the molecular characterization of DnaJ60, a gene located at 60C on the right arm of the second chromosome of Drosophila melanogaster and encoding a putative protein of 217 amino acids with a molecular mass of 27.7-kDa and a pl of 10.5. The N-terminal region of the DnaJ60 protein displays a significant sequence similarity with the J domain of DnaJ proteins and contains a centrally located hydrophobic segment suggesting the occurrence of a membrane spanning domain. Northern blot analysis detected a 0.75-kb transcript which is weakly expressed in embryos, larvae and females but intensively expressed in adult males. In situ localization revealed that the DnaJ60 transcript is highly expressed in male testes and the ejaculary bulb but at an undetectable level in ovaries suggesting that the DnaJ60 protein may play an important function during spermatogenesis and/or in the male genital tract. PMID: [9372188]
3. K. Endo, T. Akiyama, S. Kobayashi and M. Okada (1996) Degenerative spermatocyte, a novel gene encoding a transmembrane protein required for the initiation of meiosis in Drosophila spermatogenesis. Mol Gen Genet 253(1-2): 157-65.
Abstract We have identified a novel Drosophila gene, degenerative spermatocyte (des), that may be required for the initiation of meiosis in spermatogenesis. In des mutant testes, the primary spermatocytes become mature in size but degenerate without initiating meiotic chromosome condensation in their nuclei. We have mapped the locus of the des gene at 26A on the left arm of the second chromosome, and identified two related, differentially spliced transcripts (des-1, des-2) from the locus. The genomic DNA fragment encoding both transcripts is able to rescue the des phenotype when introduced into mutant flies. The expression of the des-1 transcript is significantly suppressed in the des mutant testes, whereas expression of the des-2 transcript is undetectable in both wild-type and mutant testes, indicating that the des-1 transcript encodes the des function in spermatogenesis. The des-1 transcript is selectively expressed in primary spermatocytes during normal spermatogenesis. The nucleotide sequence of the des-1 transcript predicts that it encodes a novel transmembrane protein. These results raise the possibility that the des gene product may be required for interactions between primary spermatocytes and surrounding somatic cells. PMID: [9003299]