The neonatal marmoset monkey ovary is very primitive exhibiting many oogonia

Abstract

Oogonia are characterized by diploidy and mitotic proliferation. Human and mouse oogonia express several factors such as OCT4, which are characteristic of pluripotent cells. In human, almost all oogonia enter meiosis between weeks 9 and 22 of prenatal development or undergo mitotic arrest and subsequent elimination from the ovary. As a consequence, neonatal human ovaries generally lack oogonia. The same was found in neonatal ovaries of the rhesus monkey, a representative of the old world monkeys (Catarrhini). By contrast, proliferating oogonia were found in adult prosimians (now called Strepsirrhini), which is a group of ‘lower’ primates. The common marmoset monkey (Callithrix jacchus) belongs to the new world monkeys (Platyrrhini) and is increasingly used in reproductive biology and stem cell research. However, ovarian development in the marmoset monkey has not been widely investigated. Herein, we show that the neonatal marmoset ovary has an extremely immature histological appearance compared with the human ovary. It contains numerous oogonia expressing the pluripotency factors OCT4A, SALL4, and LIN28A (LIN28). The pluripotency factor-positive germ cells also express the proliferation marker MKI67 (Ki-67), which has previously been shown in the human ovary to be restricted to premeiotic germ cells. Together, the data demonstrate the primitiveness of the neonatal marmoset ovary compared with human. This study may introduce the marmoset monkey as a non-human primate model to experimentally study the aspects of primate primitive gonad development, follicle assembly, and germ cell biology in vivo.

Postnatal oogenesis in humans: a review of recent findings

“…Ovarian development in the marmoset monkey has not been widely investigated, but the data show that the neonatal marmoset ovary contains numerous oogonia expressing several pluripotency factors such as OCT4A, SALL4, and LIN28A (LIN28). 19 Altogether, these data demonstrate the primitiveness of the neonatal marmoset ovary in comparison with the human one while also confirming that oogonia, in fact, persisted in adult ovaries through the evolutionary development of primates. Similarly, some scientific evidence exists that shows oogonia can persist into adulthood in some other prosimian species, such as lemurs.…”

“…In addition, human and mouse oogonia express several factors which are characteristic of pluripotent stem cells, such as octamer-binding transcription factor 4 (OCT4). 19 In humans, almost all oogonia enter meiosis between weeks 9 and 22 of prenatal development or undergo mitotic arrest and are eliminated from the ovaries. 19 Consequently, neonatal human ovaries generally lack oogonia.…”

“… 19 In humans, almost all oogonia enter meiosis between weeks 9 and 22 of prenatal development or undergo mitotic arrest and are eliminated from the ovaries. 19 Consequently, neonatal human ovaries generally lack oogonia. Byskov et al reported that there was no evidence for the presence of oogonia in human ovaries after their final clearance during the first 2 years of life.…”

Long‐Term Oocyte‐Like Cell Development in Cultures Derived from Neonatal Marmoset Monkey Ovary

“…We use the common marmoset monkey ( Callithrix jacchus ) as a nonhuman primate model to study reproductive and stem cell biology. In contrast to other species used in reproductive biology, the marmoset monkey still has numerous oogonia in the neonatal ovary, which robustly express the pluripotency associated markers OCT4A, LIN28, and SALL4, the germ cell marker VASA, and the proliferation marker KI-67 [ 18 ]. Therefore, these oogonia in the neonatal marmoset ovary share important pluripotency markers with marmoset monkey embryonic stem (ES) cells [ 19 ].…”

The tissue and molecular basis of folliculogenesis. The aging ovaries

“…Более того, после родов только у некоторых видов млекопитающих (наиболее примитивные приматы) незрелые половые клетки выявляются в гонадах. У человека почти все оогонии вступают в мейоз на 9-22-й неделе внутриутробного развития или останавливаются на стадии профазы I, элиминируются из фетальных яичников и не обнаруживаются в постнатальном периоде [34]. В целом данные свидетельствуют о примитивности неонатальных яичников мокроносых приматов по сравнению с человеческими, одновременно подтверждая факт персистенции оогониев во взрослых гонадах, учитывая эволюционное развитие приматов.…”