Taxonomic distribution of proteins containing DIRP domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing DIRP domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Transcription of meiotic cell cycle and terminal differentiation genes depends ona conserved chromatin associated protein, whose nuclear localisation isregulated.

White-Cooper H, Leroy D, MacQueen A, Fuller MT
Development. 2000; 127: 5463-73

The Drosophila always early (aly) gene coordinately regulates meiotic cell cycle progression and terminal differentiation during male gametogenesis. aly isrequired for transcription of key G2-M cell cycle control genes and of spermatid differentiation genes, and for maintenance of normal chromatin structure inprimary spermatocytes. We show that aly encodes a homologue of the Caenorhabditiselegans gene lin-9, a negative regulator of vulval development that acts in thesame SynMuvB genetic pathway as the LIN-35 Rb-like protein. The aly gene familyis conserved from plants to humans. Aly protein is both cytoplasmic and nuclearin early primary spermatocytes, then resolves to a chromatin-associated pattern. It remains cytoplasmic in a loss-of-function missense allele, suggesting thatnuclear localisation is critical for Aly function, and that other factors mayalter Aly activity by controlling its subcellular localisation. MAPK activationoccurs normally in aly mutant testes. Therefore aly, and by inference lin-9, act in parallel to, or downstream of, activation of MAPK by the RTK-Ras signallingpathway. We favour a model where aly may regulate cell cycle progression andterminal differentiation during male gametogenesis by regulating chromatinconformation in primary spermatocytes.