In both mammals and teleosts, the differentiation of postmeiotic spermatids to spermatozoa (spermiogenesis) is thought to be indirectly controlled by the luteinizing hormone (LH) acting through the LH/choriogonadotropin receptor (LHCGR) to stimulate androgen secretion in the interstitial Leydig cells. However, a more direct, nonsteroidal role of LH mediating the spermiogenic pathway remains unc...

Mammalian genomes encode two genes related to the TATA-box binding protein (TBP), TBP-related factors 2 and 3 (TRF2 and TRF3). Male Trf2(-/-) mice are sterile and characterized by arrested spermatogenesis at the transition from late haploid spermatids to early elongating spermatids. Despite this characterization, the molecular function of murine Trf2 remains poorly characterized and no direct e...

Human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) have been shown to differentiate into primordial germ cells (PGCs) but not into spermatogonia, haploid spermatocytes, or spermatids. Here, we show that hESCs and hiPSCs differentiate directly into advanced male germ cell lineages, including postmeiotic, spermatid-like cells, in vitro without genetic manipulation. Fur...

Although round spermatids have been studied extensively using staining techniques and electron microscopy, little information is available about their appearance in living conditions. We describe a method of collecting and identifying round spermatids from ejaculates and testicular biopsies. The validity of the selection procedure was confirmed by fluorescence in-situ hybridization. Based on ce...

We report that a 2.4-kilobase (kb) pim-1 transcript is expressed in the germ cells of mouse testis. Analysis of purified populations of spermatogenic cell types indicates that the 2.4-kb transcript is selectively expressed in haploid postmeiotic early spermatids. The evidence for a developmentally regulated expression of pim-1 in haploid spermatids suggests a possible developmental role for thi...

OBJECTIVE To determine the diagnostic features of Robertsonian (Rob) translocation (11; 13) in mice and the mechanisms underlying the effect on spermatogenesis and reproductive decline. METHODS A Rob translocation (11; 13) mouse model was established by cross-breeding, and confirmed by chromosome analysis. Chromosome aberrations and translocation patterns were identified in mice with Rob tran...

Spermatids are the earliest male germ cells with one set of haploid chromosomes. After experiments, mainly in rodents, the spermatid injection was introduced in human assisted reproduction to the treatment of men with non-obstructive azoospermia. Spermatid injection is a technique with particular difficulties that may negatively influence the outcome. The identification, isolation and the asses...

During the haploid phase of spermatogenesis, spermatids undergo a complex remodeling of the paternal genome involving the finely orchestrated replacement of histones by the highly-basic protamines. The associated striking change in DNA topology is characterized by a transient surge of both single- and double-stranded DNA breaks in the whole population of spermatids which are repaired before spe...

Mammalian spermiogenesis is marked by the morphological and functional differentiation of round haploid spermatids into mature spermatozoa. A molecular restructuring of the chromatin accompanies this process facilitated by the transition proteins and protamines which compact and condense the genetic material within the developing spermatid. Previous studies from this laboratory have demonstrate...