Drosophilaspermatid individualization is sensitive to temperature and fatty acid metabolism

Abstract

Fatty acids are precursors of potent lipid signaling molecules. They are stored in membrane phospholipids and released by phospholipase A2 (PLA2). Lysophospholipid acyltransferases (ATs) oppose PLA2 by re-esterifying fatty acids into phospholipids, in a biochemical pathway known as the Lands Cycle. Drosophila Lands Cycle ATs oys and nes, as well as 7 predicted PLA2 genes, are expressed in the male reproductive tract. Oys and Nes are required for spermatid individualization. Individualization, which occurs after terminal differentiation, invests each spermatid in its own plasma membrane and removes the bulk of the cytoplasmic contents. We developed a quantitative assay to measure individualization defects. We demonstrate that individualization is sensitive to temperature and age but not to diet. Mutation of the cyclooxygenase Pxt, which metabolizes fatty acids to prostaglandins, also leads to individualization defects. In contrast, modulating phospholipid levels by mutation of the phosphatidylcholine lipase Swiss cheese (Sws) or the ethanolamine kinase Easily shocked (Eas) does not perturb individualization, nor does Sws overexpression. Our results suggest that fatty acid derived signals such as prostaglandins, whose abundance is regulated by the Lands Cycle, are important regulators of spermatogenesis.

Combover interacts with the axonemal component Rsp3 and is required for sperm individualization

“…8, quantified in 8I), and fewer than 10% of ICs in each mutant had abnormal morphology (Fig. 8J), consistent with the range of normal ICs seen in various control genotypes (Ben-David et al, 2015). The dgo mutant showed fewer normal ICs compared with controls (Fig.…”

“…(C) Drawing of a testis showing the position of basally forming ICs in contact with nuclei (blue), as well as mature, apically moving ICs (red; arrowheads) and normal WBs (arrow). Adapted from Ben-David et al (2015). (D) Compared with wild-type (w 1118 ) and heterozygous (cmb − /TM6B) siblings, homozygous mutant cmb KO males produce no progeny when mated to wild-type females.…”

Separating from the pack: Molecular mechanisms ofDrosophilaspermatid individualization

“…In the absence of the lysophospholipid acyltransferases Oys and Nes or the cyclooxygenase Pxt, the actin cones do not migrate properly, suggesting that prostaglandin-like lipids generated from membrane phospholipids are important for this process. 57,98 When phospholipid levels are genetically manipulated, no effect is seen, indicating that specific molecules, rather than bulk phospholipids, are critical. 98 Whether these lipids play structural or signaling roles remains to be determined.…”

“…57,98 When phospholipid levels are genetically manipulated, no effect is seen, indicating that specific molecules, rather than bulk phospholipids, are critical. 98 Whether these lipids play structural or signaling roles remains to be determined.…”

“…21,78 Individualization also is very sensitive to temperature, suggesting that cellular stress can halt the process. 98 Other cell stressors have not been tested, but Wolbachia infection has been seen to induce mild individualization defects in some cases. 80 Recently, it was found that genetic perturbation of the RNAi pathway causes individualization phenotypes.…”