Genetic Analysis of the Drosophila 63F Early Puff: Characterization of Mutations in E63-1 and maggie, a Putative Tom22

Corresponding author: Andrew J. Andres, Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611-3093., andres{at}nwu.edu (E-mail)

Communicating editor: T. C. KAUFMAN

The 63F early puff in the larval salivary gland polytene chromosomes contains the divergently transcribed E63-1 and E63-2 ecdysone-inducible genes. E63-1 encodes a member of the EF-hand family of Ca²⁺-binding proteins, while E63-2 has no apparent open reading frame. To understand the functions of the E63 genes, we have determined the temporal and spatial patterns of E63-1 protein expression, as well as undertaken a genetic analysis of the 63F puff. We show that E63-1 is expressed in many embryonic and larval tissues, but the third-instar larval salivary gland is the only tissue where increases in protein levels correlate with increases in ecdysone titer. Furthermore, the subcellular distribution of E63-1 protein changes dynamically in the salivary glands at the onset of metamorphosis. E63-1 and E63-2 null mutations, however, have no effect on development or fertility. We have characterized 40 kb of the 63F region, defined as the interval between Ubi-p and E63-2, and have identified three lethal complementation groups that correspond to the dSc-2, ida, and mge genes. We show that mge mutations lead to first-instar larval lethality and that Mge protein is similar to the Tom22 mitochondrial import proteins of fungi, suggesting that it has a role in mitochondrial function.

This article has been cited by other articles:

				D. Macasev, J. Whelan, E. Newbigin, M. C. Silva-Filho, T. D. Mulhern, and T. Lithgow Tom22', an 8-kDa trans-Site Receptor in Plants and Protozoans, Is a Conserved Feature of the TOM Complex That Appeared Early in the Evolution of Eukaryotes Mol. Biol. Evol., August 1, 2004; 21(8): 1557 - 1564. [Abstract] [Full Text] [PDF]

				A. M. Bentley, B. C. Williams, M. L. Goldberg, and A. J. Andres Phenotypic characterization of Drosophila ida mutants: defining the role of APC5 in cell cycle progression J. Cell Sci., January 3, 2002; 115(5): 949 - 961. [Abstract] [Full Text] [PDF]