ABSTRACT Heterochromatin-related epigenetic mechanisms, such as DNA methylation, facilitate pairing of homologous chromosomes during the meiotic prophase mammalian spermatogenesis. In pro-spermatogonia, de novo methylation plays a key role in completing and initiating division. However, maintenance regulation meiosis, especially adult, is not well understood. Here, we reveal that NP95 (also kno...

The fresh water catfish is the most predominant species of the teleost bred in captivity in Nigeria and has provided a model for the study of reproduction in aquatic vertebrates, but information on the number of mitotic divisions and spermatogonial generations remains inconclusive. This investigation aimed at assessing the number of generations of spermatogonia produced prior to meiotic divisio...

It is controversial whether a functional androgen receptor (AR) on germ cells, including spermatogonia, is essential for their development into sperm and, thus, initiation and maintenance of spermatogenesis. It was recently shown that many spermatocytes underwent apoptosis in the testes of Hsp90α KO mice. We had generated Hsp90α KO mice independently and confirmed this phenotype. However, the i...

Human spermatogenesis includes three main stages, namely, the mitosis of spermatogonia, meiosis of spermatocytes, and spermiogenesis of spermatids, which are precisely regulated by epigenetic and genetic factors. Abnormality of epigenetic and genetic factors can result in aberrant spermatogenesis and eventual male infertility. However, epigenetic regulators in controlling each stage of normal a...

Dazl encodes an RNA-binding protein essential for spermatogenesis. Mice that are deficient for Dazl are infertile, lacking any formation of spermatozoa, and the only germ cells present are spermatogonia and a few spermatocytes. To gain more insight regarding the timing of the spermatogenic arrest in Dazl 2/2 mice, we studied the spermatogonial cell types present in testis sections and in semini...

background: there are numerous investigations on wide range of issues that disrupt regulatory spermatogenesis, individuals who are exposed to drug abuse faced infertility and immature spermatogenesis. objective: the aim of this study was to evaluate the addiction effects of morphine and its derivatives on rats spermatogenesis. materials and methods: 40 male wistar rats were randomly divided int...

Spermatogenesis is a dynamic developmental process requiring precisely timed transitions between discrete stages. Specifically, the germline undergoes three transitions: from mitotic spermatogonia to spermatocytes, from meiotic spermatocytes to spermatids, and from morphogenetic spermatids to spermatozoa. The somatic cells of the testis provide essential support to the germline throughout sperm...

Spermatogenesis is a continuous and highly coordinated process of spermatozoa production. In mice, this process is believed to initiate shortly after birth with the emergence of nascent spermatogonia in the testes. However, because the nascent spermatogonia originated from the gonocytes are morphologically indistinguishable from their predecessors and there is no clear definition for the gonocy...

BACKGROUND Spermatogonial expansion in man and non-human primates has been studied for decades. Controversy persists about the cell type representing the testicular stem cell and the exact kinetics of spermatogonial proliferation. We recently determined the starting point of spermatogenesis and proposed a model for clonal expansion of spermatogonia in adult macaques. Here we want to confirm the...

The underlying primary damage to the testis caused by chemotherapeutic regimens during childhood is largely unknown. Xenografting of monkey testes was successfully applied in maturation of juvenile testis to the point of complete spermatogenesis. This allows us to manipulate developing primate testis without direct treatment of patients. This new model is validated establishing the effects of c...