Germ cell differentiation in the marmoset (Callithrix jacchus) during fetal and neonatal life closely parallels that in the human.
BACKGROUND
Testicular germ cell tumours (TGCT) are thought to originate from fetal germ cells that fail to differentiate normally, but no animal model for these events has been described. We evaluated the marmoset (Callithrix jacchus) as a model by comparing perinatal germ cell differentiation with that in humans.


METHODS
Immunohistochemical profiling was used to investigate germ cell differentiation (OCT4, NANOG, AP-2gamma, MAGE-A4, VASA, NANOS-1) and proliferation (Ki67) in fetal and neonatal marmoset testes in comparison with the human and, to a lesser extent, the rat.


RESULTS
In marmosets and humans, differentiation of gonocytes into spermatogonia is associated with the gradual loss of pluripotency markers such as OCT4 and NANOG, and the expression of germ cell-specific proteins such as VASA. This differentiation occurs asynchronously within individual cords during fetal and early postnatal life. This contrasts with rapid and synchronous germ cell differentiation within and between cords in the rat. Similarly, germ cell proliferation in the marmoset and human occurs throughout perinatal life, in contrast to rats in which proliferation ceases during this period.


CONCLUSIONS
The marmoset provides a good model for normal human germ cell differentiation and proliferation. The perinatal marmoset may be a useful model in which to establish factors that lead to failure of normal germ cell differentiation and the origins of TGCT.
Mitchell
R T
RT
MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh, Scotland, UK. r.mitchell@hrsu.mrc.ac.uk
Cowan
G
G
Morris
K D
KD
Anderson
R A
RA
Fraser
H M
HM
Mckenzie
K J
KJ
Wallace
W H B
WH
Kelnar
C J H
CJ
Saunders
P T K
PT
Sharpe
R M
RM
D000818:Animals; D000831:Animals, Newborn; D002144:Callithrix / Q000196:embryology*; D002454:Cell Differentiation; D049109:Cell Proliferation; D053487:DEAD-box RNA Helicases / Q000096:biosynthesis; D005854:Germ Cells / Q000166:cytology*; D018398:Homeodomain Proteins / Q000096:biosynthesis; D006801:Humans; D008297:Male; D023421:Models, Animal; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000096:biosynthesis; D016601:RNA-Binding Proteins / Q000096:biosynthesis; D051381:Rats; D013093:Spermatogonia / Q000378:metabolism; D013737:Testis / Q000166:cytology / Q000196:embryology; D050656:Transcription Factor AP-2 / Q000096:biosynthesis
D018398:Homeodomain Proteins; C486780:NANOG protein, human; C515170:NANOS1 protein, human; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3; D016601:RNA-Binding Proteins; D050656:Transcription Factor AP-2; C498288:DDX4 protein, human; D053487:DEAD-box RNA Helicases