This proposal is for support of research to investigate a new organelle of male mammalian germ cells termed a dictyosome-like structure (DLS). This organelle occurs in guinea pig spermatocytes and spermatids in large numbers and has been noted in testes of other species including primates. The DLS superficially resemble conventional Golgi apparatus in that they are composed of stacks of 2-17 saccules; each saccule averages about 200 A in thickness (membrane plus lumen) and is separated from adjacent saccules in the stack by an intersaccular space of about 120 A. They are readily distinguished from Golgi apparatus by distinct intersaccular bridging elements that consist of fiber bundies connected to annuli of about 100 A in diameter. These bridging elements often appear in linear arrays or in clusters of 3-4. Although bearing a distinct resemblence to Golgi apparatus, DLS and Golgi apparatus coexist in the same cell. The presence of the bridging elements makes the DLS clearly different from Golgi apparatus and places it as a candidate as a new organelle unique to certain stages of spermatogenesis. Because DLS contain distinct intersaccular bridging elements and appear to carry out some function related to acquisition of specific surface characteristics unique to late stages of germ cell development in the testis, these structures emerge as potential targets for development of drugs applicable to control of fertility in the male. The objectives of this proposal are to study DLS of testis germ cells to learn: 1) More about the structure, function and distribution among species of the intersaccular bridging elements and to what extent the DLS (and especially the bridging elements) may contain unique macromolecules against which specific blocking drugs could be developed, 2) the origin and fate of DLS (an origin from thick cisternae at the mature or trans face of the Golgi apparatus and ultimate association with the plasma membrane is assumed from indirect evidence) and 3) the chemical nature of the glycolipids that contribute to unique staining of DLS and of sperm plasma membrane. An approach is emphasized that combines information from cell fractionation and biochemical analysis with information from electron microscopy and cytochemistry.
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