Toward a More Precise and Informative Nomenclature Describing Fetal and Neonatal Male Germ Cells in Rodents1

Abstract

The germ cell lineages are among the best characterized of all cell lineages in mammals. This characterization includes precise nomenclature that distinguishes among numerous, often subtle, changes in function or morphology as development and differentiation of germ cells proceed to form the gametes. In male rodents, there are at least 41 distinct cell types that occur during progression through the male germ cell lineage that gives rise to spermatozoa. However, there is one period during male germ cell development-that which occurs immediately following the primordial germ cell stage and prior to the spermatogonial stage-for which the system of precise and informative cell type terminology is not adequate. Often, male germ cells during this period are referred to simply as "gonocytes." However, this term is inadequate for multiple reasons, and it is suggested here that nomenclature originally proposed in the 1970s by Hilscher et al., which employs the terms M-, T1-, and T2-prospermatogonia, is preferable. In this Minireview, the history, proper utilization, and advantages of this terminology relative to that of the term gonocytes are described.

DMRT proteins and coordination of mammalian spermatogenesis

“…Thus the arrested mutant cells are similar to embryonic proSGs (McCarrey, 2013). This phenotype is similar in some respects to that of Rhox10 mutants, which also have defects in early postnatal germ cell migration and establishment of SSCs (Song et al, 2016).…”

Cell-Surface DEAD-Box Polypeptide 4-Immunoreactive Cells and Gonocytes Are Two Distinct Populations in Postnatal Porcine Testes1

“…Two primer pairs were used to amplify the N-terminus (exons 1-3) and the C-terminus (exons [19][20]. The qRT-PCR analysis using either primer combination showed 22-and 17-fold lower DDX4 mRNA levels in G4 cells than those in G3 cells (Fig.…”

“…During the prespermatogenesis period, gonocytes (also referred to as prospermatogonia), which are the precursors of spermatogonial stem cells (SSCs), are the only germ cell population in the testes [17][18][19]. We first cloned porcine DDX4 (pDDX4) cDNA from neonatal testis and overexpressed recombinant DDX4 in COS-1 cells to confirm cross-species reactivity of the antihuman DDX4 antibody, which has been used for identification of cell-surface DDX4-immunoreactive ovarian cells [9,10] and germ cells in various mammalian species [8,[20][21][22].…”

The Homeobox Transcription Factor RHOX10 Drives Mouse Spermatogonial Stem Cell Establishment

“…M-ProSG give rise to primary transitional (T1) ProSG, which are mitotically silent but molecularly active, as they reestablish DNA methylation marks erased in M-ProSG and PGCs. Upon resumption of mitosis, T1-ProSG become secondary transitional (T2) ProSG, which are regarded as the immediate precursor cells that give rise to SSCs (McCarrey, 2013). A unique feature of T2 ProSG is that they are migratory, a characteristic that allows them to traverse from the center of the seminiferous epithelial tubule to its periphery.…”

“…ProSG are regarded as the cellular precursors of not only SSCs but also differentiating A-spermatogonia, the cells responsible for the first wave of spermatogenesis (Culty, 2013; McCarrey, 2013). This first wave, which bypasses the SSC step, was likely selected for over evolutionary time because it permits rapid generation of sperm, thereby bestowing fertility to young males.…”