Expression Of Dysbindin-1 During Spermatogenesis

Objective:Dysbindin-1 is a subunit of biogenesis of lysosome-related organelles complex-1(BLOC-1), which plays an important role in the formation of lysosome-related organelles(LROs). LROs, such as melanosomes and platelet-dense granules, are derived from the Golgi complex, similar to lysosomes, with low p H value. In addition, LROs contain some cell-type specific components that are responsible for specific morphology and function, BLOC-1 is one complex composed of eight subunits, involved in intracellular vesicle formation and transport process.Acrosome is categorized as a LRO existing on the head of spermatozoa, and plays an important part in fertilization. So far the function of dysbindin-1 in the testis is unclear.Recent study has shown that RNF151 has a direct interaction with dysbindin-1. RNF151 is specifically expressed in elongated spermatid and dysbindin-1 is speculated to play a role in the formation of the spermatid acrosome considering that dysbindin-1 has significant function in vesicular trafficking. There is no experimental evidence for whether dysbindin-1 is involved in acrosome formation.To test dysbindin-1 expression during spermatogenesis and dysbindin-1 effect on histology of acrosome in mice, which provides necessary morphologic basis for further function study on dysbindin-1 in the spermatogenesis.Methods:Western blot analysis was applied to detect the expression of dysbindin-1 in testis on day 6-20, 21, 28, 35 and 42 postpartum and three-month old mice( n=3), and HE staining was performed for testis morphology. Collecting the caudal spermatozoa from sdy mice(no dysbindin-1 expression), one part were used to detect the expression of dysbindin-1 by western blot, the other part were prepared for sperm smears. HE staining was performed for sperm morphology, fluorescein isothiocyanate conjugate-pisum sativum agglutinin(FITC-PSA) staining and immunofluorescence staining with antibody against sperm protein 56(sp56) for acrosome on sperm smearResults:1.Dysbindin-1A, not-1C, was expressed in testis and epididymis tissues of differernt wild type adult mice.2.Dysbindin-1A was expressed in postnatal testis development. Also, on 7 postpartum day, dysbindin-1A has been expressed, and on 14, 21 as well as 28 postpartum day, the expression of dysbindin-1A is a growing tendency, until on 35 and 42 postpartum day,there is a slight decline, which is no significant difference(P>0.05). Dysbindin-1A is mainly enriched in the cytoplasm of testis.3.Histology structure of sdy sperm and acrosome, compared to wild type mice,showed no abnormalities.Conclusion:Dysbindin-1A, expressed in testis tissue and sperm during spermatogenesis, is not required for maintain the morphology of sperm.