Spermatogenesis is a sophisticated biological process responsible for development of spermatozoa from spermatogonial stem cells (1, 2, 3, 4). The process includes stem-cell renewal and differentiation, genome reorganization and half reduction, and genome repackaging and cellular transformation (5, 6). During the continuous process, the intricate interaction between spermatogenetic cell and somatic cell is elaborately regulated. Generally, it has been divided into three distinct stages: premeiotic, meiotic, and postmeitoic stages (7). At the premeiotic stage, renewal and differentiation of spermatogonial stem cells (SSC) and mitotic proliferation of spermatogonia occur (2, 8, 9). After that, the type B spermatogonia enter into meiosis, and are transformed into spermatocytes (8). During the meiotic stage, the genomes of primary spermatocytes are halved into secondary spermatocytes; In the process of postmeiotic stage (also termed as spermiogenesis), the secondary spermatocytes are formed into round spermatids because of chromatin and nuclear condensation (10). Transformation of round spermatids into enlongated spermatids, finally spermatozoa, ascribes to rearrangement of cytoskeletal structure and genome repackaging (11, 12). In the whole stages, two somatic cells play a vital role in mammalian spermatogenesis, one of them is leydig cells, which secretes testosterone, stimulating sertoli cells (the other one of them),direct contact with differentiating germ cells, to support spermatogenesis in the seminiferous tubules（see figure below） (5, 13, 14, 15, 16, 17). Inappropriate coordination of these events result in spermatogenic pathologies such as spermatogenic arrest, Sertoli cell only syndrome (SCO) and even sterility. Although great progress has been made by the genetic modification of model animals, the molecular mechanisms of spermatogenesis still remain to be discovered.
The spermatogenesis is long lasting and complex process, although many proteins have been identified to be implicated in it, an integrated resource in this area still remains unavailable. In this work, we collected all proteins identified to play roles or potential roles in spermatogenesis. After manually curated, XX records correspondent to XX proteins has been confirmed to be involved in the spermatogenesis. Then, an integrated and searchable database Spermtogenesis Online 1.0 has been founded. It is the first integrative resource embracing the most of identified components and related scientific information of spermatogenesis.
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1. Sertoli cell 2. Leydig cell 3. Spermatogonium 4. Spermatocyte 5. Spermatid 6. Spermatozoon