Abstract: 【Aim】 To explore the effect of piwi knock-down on hemocyte proliferation and differentiation in Drosophila melanogaster. 【Methods】 The D. melanogaster strains e33C-Gal4 and Hml-Gal4-UAS-2×EGFP were crossed with the wild strain w¹¹¹⁸ and the strain UAS-piwi RNAi, respectively, to reduce the expression of piwi gene in circulating hemocytes or lymph glands of D. melanogaster. The localization of Piwi protein in hemocytes and its effect on hemocyte proliferation and differentiation in D. melanogaster were detected by immunofluorescence staining. 【Results】 Piwi protein was expressed in circulating hemocytes and the whole lymph glands of D. melanogaster, and was mainly localized in the cytoplasm. The knock-down of piwi gene resulted in significant increase in the number of circulating hemocytes and the number of cells in the M phase of mitosis, but the differentiation of plasmatocytes and lamellocytes in circulating hemocytes were not affected. The knock-down of piwi gene had no effect on the proliferation of lymph gland hemocytes, but resulted in the excessive differentiation of plasmatocytes and the generation of lamellocytes. 【Conclusion】 The knock-down of piwi gene in circulating hemocytes in Drosophila can induce the overproliferation of hemocytes, while the knockdown of piwi gene in lymph glands can induce abnormal differentiation of hemocytes.

Key words: Drosophila melanogaster, piwi, lymph gland, hemocytes, proliferation and differentiation, immunofluorescence staining