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Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testicle. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules. [ 1 ]
Around 50% of the SSC population undergo self-renewal to maintain stem cell numbers, and the other 50% become committed progenitor cells that will differentiate into spermatozoa during spermatogenesis. [21] Cells present in the testes express molecules that play key roles in the regulation of SSC self-renewal.
Spermatogenesis occurs in the germinal epithelium of the seminiferous tubules. Spermatogonia undergo meiosis to produce spermatids that later mature into spermatozoa. The spermatogonia duplicate their DNA to obtain 46 chromosomes in preparation for the primary division. At this stage, the germ cells are now referred to as primary spermatocytes. [3]
The exogenous DNA interacts with the DNA-binding proteins (DBPs) that are present on the surface of the sperm cell. 3 Spermatozoa are naturally protected against the intrusion of exogenous DNA molecules by an inhibitory factor present in mammals’ seminal fluid. This factor blocks the binding of sperm cells and exogenous DNA because in the ...
The sperm genome is unable to undergo transcription during spermiogenesis, impeding its ability to respond to new challenges, such as DNA damage. [ 5 ] Associated with proper genome packaging to create mature germ cells there is a transition from histone protein binding to protamine protein binding and this transition is associated with ...
Because its main function is to nourish developing sperm cells through the stages of spermatogenesis, the Sertoli cell has also been called the "mother" or "nurse" cell. [10] Sertoli cells also act as phagocytes, consuming the residual cytoplasm during spermatogenesis. Translocation of cells from the basal lamina to the lumen of the ...
During mouse spermatogenesis, the mutation frequencies of cells at the different stages, including pachytene spermatocytes, are 5 to 10-fold lower than the mutation frequencies in somatic cells. [11] Because of their elevated DNA repair capability, spermatocytes likely play a central role in the maintenance of these lower mutation rates, and ...
Acrosome reaction on a sea urchin cell. For fertilization to happen between a sperm and egg cell, a sperm must first fuse with the plasma membrane and then penetrate the female egg cell to fertilize it.