TY - JOUR
T1 - The Drosophila Neprilysin 4 gene is essential for sperm function following sperm transfer to females
AU - Ohsako, Takashi
AU - Shirakami, Machi
AU - Oiwa, Kazuharu
AU - Ibaraki, Kimihide
AU - Karr, Timothy L.
AU - Tomaru, Masatoshi
AU - Sanuki, Rikako
AU - Takano-Shimizu-kouno, Toshiyuki
N1 - Funding Information:
We thank D. M. McKearin, the National BioResource Project (KYOTO Stock Center), Bloomington Drosophila Stock Center and Vienna Drosophila Resource Center for fly stocks. This work was supported by JSPS KAKENHI Grant Numbers JP16K07463 and JP19K06780 to T. T.-S.-K. and M. T.
Publisher Copyright:
© 2021 The Author(s).
PY - 2021
Y1 - 2021
N2 - Sperm are modified substantially in passing through both the male and the female reproductive tracts, only thereafter becoming functionally competent to fer-tilize eggs. Drosophila sperm become motile in the seminal vesicle; after ejacula-tion, they interact with seminal fluid proteins and undergo biochemical changes on their surface while they are stored in the female sperm storage organs. How-ever, the molecular mechanisms underlying these maturation processes remain largely unknown. Here, we focused on Drosophila Neprilysin genes, which are the fly orthologs of the mouse Membrane metallo-endopeptidase-like 1 (Mmel1) gene. While Mmel1 knockout male mice have reduced fertility without abnormal-ity in either testis morphology or sperm motility, there are inconsistent results regarding the association of any Neprilysin gene with male fertility in Drosophila. We examined the association of the Nep1–5 genes with male fertility by RNAi and found that Nep4 gene function is specifically required in germline cells. To investigate this in more detail, we induced mutations in the Nep4 gene by the CRISPR/Cas9 system and isolated two mutants, both of which were viable and female fertile, but male sterile. The mutant males had normal-looking testes and sperm; during copulation, sperm were transferred to females and stored in the seminal receptacle and paired spermathecae. However, following sperm transfer and storage, three defects were observed for Nep4 mutant sperm. First, sperm were quickly discarded by the females; second, the proportion of eggs fertilized was significantly lower for mutant sperm than for control sperm; and third, most eggs laid did not initiate development after sperm entry. Taking these observations together, we conclude that the Nep4 gene is essential for sperm function following sperm transfer to females.
AB - Sperm are modified substantially in passing through both the male and the female reproductive tracts, only thereafter becoming functionally competent to fer-tilize eggs. Drosophila sperm become motile in the seminal vesicle; after ejacula-tion, they interact with seminal fluid proteins and undergo biochemical changes on their surface while they are stored in the female sperm storage organs. How-ever, the molecular mechanisms underlying these maturation processes remain largely unknown. Here, we focused on Drosophila Neprilysin genes, which are the fly orthologs of the mouse Membrane metallo-endopeptidase-like 1 (Mmel1) gene. While Mmel1 knockout male mice have reduced fertility without abnormal-ity in either testis morphology or sperm motility, there are inconsistent results regarding the association of any Neprilysin gene with male fertility in Drosophila. We examined the association of the Nep1–5 genes with male fertility by RNAi and found that Nep4 gene function is specifically required in germline cells. To investigate this in more detail, we induced mutations in the Nep4 gene by the CRISPR/Cas9 system and isolated two mutants, both of which were viable and female fertile, but male sterile. The mutant males had normal-looking testes and sperm; during copulation, sperm were transferred to females and stored in the seminal receptacle and paired spermathecae. However, following sperm transfer and storage, three defects were observed for Nep4 mutant sperm. First, sperm were quickly discarded by the females; second, the proportion of eggs fertilized was significantly lower for mutant sperm than for control sperm; and third, most eggs laid did not initiate development after sperm entry. Taking these observations together, we conclude that the Nep4 gene is essential for sperm function following sperm transfer to females.
KW - Drosophila
KW - Mmel1
KW - Neprilysin genes
KW - female sperm storage
KW - male sterility
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U2 - 10.1266/ggs.21-00024
DO - 10.1266/ggs.21-00024
M3 - Article
C2 - 34556622
AN - SCOPUS:85122772821
SN - 1341-7568
VL - 96
SP - 177
EP - 186
JO - Genes and Genetic Systems
JF - Genes and Genetic Systems
IS - 4
ER -