Maternal function of a retroviral-type zinc-finger protein is essential for Drosophila development.
Previous studies have shown that zygotic expression of the Drosophila lark gene, which encodes an RNA-binding protein, is essential for embryogenesis. We now show that lark mRNA is abundant in preblastoderm (0-2 h) embryos, prior to zygotic transcription, indicative of maternal inheritance. Lark can also be detected within the nurse cells of developing egg chambers, suggesting a function for the protein during oogenesis. To test the hypothesis that the maternal inheritance of lark is required for oogenesis or early development, we employed the "FLP-DFS" technique to eliminate the lark maternal component within the germ line. Unfertilized and fertilized eggs lacking the lark maternal component exhibit a "fragile" phenotype, indicating that the protein functions during oogenesis. Furthermore, differentiation of the fertilized eggs is abnormal-most embryos arrest prior to blastoderm formation and exhibit morphological phenotypes that might reflect underlying defects in syncytial nuclear cycling or cellularization. Mutational analysis of a retroviral-type zinc finger within the lark protein indicates that it is required for the maternal function of the protein: females are completely sterile when their only source of lark protein contains a zinc-finger mutation. The aggregate of our studies shows that the germ-line expression of lark is essential for development, and suggests that the retroviral-type zinc finger mediates important RNA-binding functions during oogenesis and/or early development.
McNeil
G P
GP
Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
Zhang
X
X
Roberts
M
M
Jackson
F R
FR
D000818:Animals; D004330:Drosophila / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009866:Oogenesis; D010063:Ovum; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016335:Zinc Fingers
D029721:Drosophila Proteins; D019476:Insect Proteins; C105214:Lark protein, Drosophila; D012333:RNA, Messenger; D016601:RNA-Binding Proteins