The LAMMER Protein Kinase Encoded by the Doa Locus of Drosophila Is Required in Both Somatic and Germline Cells and Is Expressed as Both Nuclear and Cytoplasmic Isoforms Throughout Development

, Robert Farka

Corresponding author: Leonard Rabinow, Laboratoire d'Embryologie Moléculaire, Bâtiment 445, Université de Paris XI, 91405 Orsay Cedex, France., lenny.rabinow{at}emex.u-psud.fr (E-mail)

Communicating editor: J. A. BIRCHLER

Activity of the Darkener of apricot (Doa) locus of Drosophila melanogaster is required for development of the embryonic nervous system, segmentation, photoreceptor maintenance, normal transcription, and sexual differentiation. The gene encodes a protein kinase, with homologues throughout eukaryotes known as the LAMMER kinases. We show here that DOA is expressed as at least two different protein isoforms of 105 and 55 kD throughout development, which are primarily localized to the cytoplasm and nucleus, respectively. Doa transcripts and protein are expressed in all cell types both during embryogenesis and in imaginal discs. Although it was recently shown that DOA kinase is essential for normal sexual differentiation, levels of both kinase isoforms are equal between the sexes during early pupal development. The presence of the kinase on the cell membrane and in the nuclei of polytene salivary gland cells, as well as exclusion from the nuclei of specific cells, may be indicative of regulated kinase localization. Mosaic analysis in both the soma and germline demonstrates that Doa function is essential for cell viability. Finally, in contrast to results reported in other systems and despite some phenotypic similarities, genetic data demonstrate that the LAMMER kinases do not participate in the ras-MAP kinase signal transduction pathway.

This article has been cited by other articles:

				J. Z. Morris, C. Navarro, and R. Lehmann Identification and Analysis of Mutations in bob, Doa and Eight New Genes Required for Oocyte Specification and Development in Drosophila melanogaster Genetics, August 1, 2003; 164(4): 1435 - 1446. [Abstract] [Full Text] [PDF]

				J. Prasad and J. L. Manley Regulation and Substrate Specificity of the SR Protein Kinase Clk/Sty Mol. Cell. Biol., June 15, 2003; 23(12): 4139 - 4149. [Abstract] [Full Text] [PDF]

				S. Savaldi-Goldstein, D. Aviv, O. Davydov, and R. Fluhr Alternative Splicing Modulation by a LAMMER Kinase Impinges on Developmental and Transcriptome Expression PLANT CELL, April 1, 2003; 15(4): 926 - 938. [Abstract] [Full Text] [PDF]

				R. Katsu, H. Onogi, K. Wada, Y. Kawaguchi, and M. Hagiwara Novel SR-rich-related Protein Clasp Specifically Interacts with Inactivated Clk4 and Induces the Exon EB Inclusion of Clk J. Biol. Chem., November 8, 2002; 277(46): 44220 - 44228. [Abstract] [Full Text] [PDF]