Flagellar mitochondrial association of the male-specific Don Juan protein in Drosophila spermatozoa.
The Drosophila don juan gene encodes a basic protein (Don Juan protein), which is solely expressed postmeiotically during spermiogenesis in elongated spermatids and in mature sperm. Transgenic expression of a GFP-tagged Don Juan protein (DJ-GFP) in the male germ line showed an association of the fusion protein with the sperm tail. Detailed examination of DJ-GFP localization revealed novel insights into its distinct temporal and spatial distribution along the sperm tail during the last phase of spermatid maturation. Co-localization of DJ-GFP with actin-labeled cysts demonstrated its emergence in elongated spermatids during individualization. Additionally, the endogenous Don Juan protein was detected with epitope-specific antibodies in finally elongated nuclei of spermatids. After completion of nuclear shaping Don Juan is no longer detectable in the sperm heads with the onset of individualization. Mislocalization of the DJ-GFP protein in flagella of a mutant with defective mitochondrial differentiation provides evidence of mitochondrial association of the fusion protein with flagellar mitochondrial arrays. Ectopically expressed DJ-GFP in premeiotic germ cells as well as salivary gland cells confirmed the capability of the fusion protein to associate with mitochondria. Therefore we suppose that Don Juan is a nuclear-encoded, germ-cell specifically expressed mitochondrial protein, which might be involved in the final steps of mitochondrial differentiation within the flagellum.
Santel
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A
Zoologie-Entwicklungsbiologie und Molekulargenetik am Fachbereich Biologie, Philipps-Universität Marburg, Karl-von-Frisch-Strasse, Germany.
Blümer
N
N
Kämpfer
M
M
Renkawitz-Pohl
R
R
D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D005455:Fluorescent Antibody Technique; D020558:GTP Phosphohydrolases / Q000032:analysis; D015870:Gene Expression / Q000502:physiology; D018095:Germ-Line Mutation; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents; D019476:Insect Proteins / Q000032:analysis / Q000235:genetics*; D008164:Luminescent Proteins / Q000235:genetics; D008297:Male; D008540:Meiosis / Q000502:physiology; D008565:Membrane Proteins / Q000032:analysis; D008928:Mitochondria / Q000737:chemistry*; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics; D012469:Salivary Glands / Q000737:chemistry; D013082:Sperm Tail / Q000737:chemistry*; D013087:Spermatids / Q000737:chemistry* / Q000166:cytology
D029721:Drosophila Proteins; D007202:Indicators and Reagents; D019476:Insect Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; C108109:dj protein, Drosophila; D049452:Green Fluorescent Proteins; C107312:Fzo protein, Drosophila; D020558:GTP Phosphohydrolases