Drosophila Oogenesis


Oogenesis is the process by which germ cells develop into eggs. Insect ovaries are classified into different types based on the morphology of the mature ovary, but in most insects they follow a common general pattern of development. In the fruitfly Drosophila, oogenesis begins with the formation of a 16‐cell cyst of interconnected germ cells, one of which will become an oocyte and mature into an egg. Cysts are produced by germline stem cells that remain active throughout the lifetime of the fly. The entire process of oogenesis, from germline stem cell to mature egg, takes about a week and depends on complex interactions between the different germ cells in a cyst and between the germ cells and the many different types of somatic cells that surround them. Given here is an overview of the morphology and development of the Drosophila ovary and cyst.

Key Concepts

  • Insect ovaries are classified on the basis of the morphology of the mature ovary.
  • Pole cells, the precursors of germ cells, are formed early in embryogenesis.
  • Germ cell formation depends on pole plasm, a specialised cytoplasm containing proteins that regulate the translation of specific mRNAs.
  • Drosophila oocytes develop in egg chambers, which are cysts of 16 interconnected germ cells enveloped by somatic follicle cells.
  • Oocyte differentiation depends on the fusome, a germ‐cell‐specific organelle.
  • Most of the oocyte's cytoplasm is made in the nurse cells and transported into the oocyte, which allows the oocyte's nucleus to remain quiescent.

Keywords: insect; ovary; oocyte; pole cell; germ cell; fusome

Figure 1. Diagram of Drosophila ovary development. Germ cells are depicted in yellow, somatic cells of the ovary are depicted in blue, anterior is to the left, and all stages (not to scale) are shown from a lateral perspective, with only one of the two gonads visible. Pole cells form at the posterior end of the early embryo (a) and migrate inward during gastrulation, where they contact somatic mesodermal cells to form embryonic gonads (b). In the larva (c), the gonads reorganise into individual ovarioles, and germ cells develop into germline stem cells. In the adult fly (d), stem cells divide continuously, producing daughter cells that develop into mature eggs. A typical female fly will lay hundreds of eggs (e) in her lifetime.
Figure 2. Diagram of a Drosophila ovary (a), ovariole (b), and egg chamber (c), not to scale. Anterior is up, posterior is down. Germ cells are shown in yellow, yolk uptake in the ovariole (b) in red, somatic support cells at the tip of the germarium in green and somatic follicle cells, which envelop germline cysts, in blue. The egg chamber (c) is at stage 8; the oodyte (ooc) has begun to take up yolk but has not yet grown larger than its sibling nurse cells.
Figure 3. (a) Diagram of a germarium. Anterior is to the left. The three regions of the germarium (1, 2 and 3) and position of an oocyte (ooc) are indicated. Terminal filament (dark green) and cap (light green) cells send signals (arrows) that maintain adjacent germline stem cells (yellow). Dividing cystocytes (light yellow) are wrapped by escort cells (purple). Fusomes (red) are round in stem cells and become elongated and branched in older cysts. Follicle cells (blue) envelop germline cysts. (b) Diagram of a germline cyst showing the pattern of connections between the oocyte and its sibling nurse cells. The direction of transport of materials into the oocyte is indicated (red arrowheads).


Becalska AN and Gavis ER (2009) Lighting up mRNA localization in Drosophila oogenesis. Development 136: 2493–2503.

Büning J (1994) The Insect Ovary: Ultrastructure, Previtellogenic Growth and Evolution. New York, NY: Chapman & Hall.

de Cuevas M, Lilly MA and Spradling AC (1997) Germline cyst formation in Drosophila. Annual Review of Genetics 31: 405–428.

de Cuevas M and Spradling AC (1998) Morphogenesis of the Drosophila fusome and its implications for oocyte specification. Development 125: 2781–2789.

Eliazer S and Buszczak M (2011) Finding a niche: studies from the Drosophila ovary. Stem Cell Research & Therapy 2: 45. DOI: 10.1186/scrt86.

Ephrussi A and Lehmann R (1992) Induction of germ cell formation by oskar. Nature 358: 387–392.

Hudson AM and Cooley L (2002) Understanding the function of actin‐binding proteins through genetic analysis of Drosophila oogenesis. Annual Review of Genetics 36: 455–488.

Huynh JR and St. Johnston D (2004) The origin of asymmetry: early polarisation of the Drosophila germline cyst and oocyte. Current Biology 14: R438–R449.

Koch EA and King RC (1966) The origin and early differentiation of the egg chamber of Drosophila melanogaster. Journal of Morphology 119: 283–303.

Lasko P (2013) The DEAD‐box helicase Vasa: evidence for a multiplicity of functions in RNA processes and developmental biology. Biochimica et Biophysica Acta 1829: 810–816.

Lighthouse DV, Buszczak M and Spradling AC (2008) New components of the Drosophila fusome suggest it plays novel roles in signaling and transport. Developmental Biology 317: 59–71. DOI: 10.1016/j.ydbio.2008.02.009.

Mahowald AP (2001) Assembly of the Drosophila germ plasm. International Review of Cytology 203: 187–213.

Montell DJ, Yoon WH and Starz‐Gaiano M (2012) Group choreography: mechanisms orchestrating the collective movement of border cells. Nature Reviews Molecular Cell Biology 13: 631–645. DOI: 10.1038/nrm3433.

Morris LX and Spradling AC (2011) Long‐term live imaging provides new insight into stem cell regulation and germline‐soma coordination in the Drosophila ovary. Development 138: 2207–2215. DOI: 10.1242/dev.065508.

Peterson JS and McCall K (2013) Combined inhibition of autophagy and caspases fails to prevent developmental nurse cell death in the Drosophila melanogaster ovary. PLoS One 8: e76046.

Roth S and Lynch JA (2009) Symmetry breaking during Drosophila oogenesis. Cold Spring Harbor Perspectives in Biology 1: a001891. DOI: 10.1101/cshperspect.a001891.

Santos AC and Lehmann R (2004) Germ cell specification and migration in Drosophila and beyond. Current Biology 14: R578–R589.

Saxe JP and Lin H (2011) Small noncoding RNAs in the germline. Cold Spring Harbor Perspectives in Biology 3: a002717. DOI: 10.1101/cshperspect.a002717.

Snapp EL, Iida T, Frescas D, Lippincott‐Schwartz J and Lilly MA (2004) The fusome mediates intercellular endoplasmic reticulum connectivity in Drosophila ovarian cysts. Molecular Biology of the Cell 15: 4512–4521.

Spradling AC (1993) Developmental genetics of oogenesis. In: Bate M and Martinez‐Arias A, (eds). The Development of Drosophila melanogaster, vol. 1. Cold Spring Harbor, NY: Cold Spring Harbor Press; pp. 1–70.

Telfer WH (1975) Development and physiology of the oocyte‐nurse cell syncytium. Advances in Insect Physiology 11: 223–319.

Theurkauf WE, Alberts BM, Jan YN and Jongens TA (1993) A central role for microtubules in the differentiation of Drosophila oocytes. Development 118: 1169–1180.

Xie T (2013) Control of germline stem cell self‐renewal and differentiation in the Drosophila ovary: concerted actions of niche signals and intrinsic factors. Wiley Interdisciplinary Reviews: Developmental Biology 2: 261–273. DOI: 10.1002/wdev.60.

Further Reading

Alberts B, Johnson A, Lewis J, et al. (2007) Molecular Biology of the Cell, 5th edn. New York, NY: Garland Science.

Weigmann K, Klapper R, Strasser T et al. (2003) FlyMove – a new way to look at development of Drosophila. Trends in Genetics 19: 310–311. http://flymove.uni‐muenster.de

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de Cuevas, Margaret(Feb 2015) Drosophila Oogenesis. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0001502.pub2]