Ye et al., 2019 - Abundance of Early Embryonic Primordial Germ Cells Promotes Zebrafish Female Differentiation as Revealed by Lifetime Labeling of Germline. Marine biotechnology (New York, N.Y.)   21(2):217-228 Full text @ Mar. Biotechnol.

Fig. 1

Generation and characterization of Tg(piwil1:egfp-UTRnos3)ihb327Tga The structure of the transcriptional regulatory region of piwil1 locus of zebrafish and the sketch map of transgenic elements. b–h Germ cell-specific expression at various developmental stages as indicated in the figure (arrows indicate the EGFP-positive germ cells; outlines indicate the swim bladder). g Dissected adult testis. h Dissected adult ovary (arrows indicate EGFP-positive oogonia or early stage of oocytes). i–k Immunofluorescence of Vasa in the transgenic embryo at 1 dpf. The selected region for imaging is indicated by a red box. iEGFP; j anti-Vasa; k merged channel

Fig. 2

Using live tracing to study the correlation between the initial PGC numbers and sexual development. a Representative images of PGC-less and PGC-rich embryos at 1 dpf (a1, a5), 5 dpf (a2, a6), and 7 dpf (a3, a7). b Representative images of PGC-less and PGC-rich larva fish at 11 dpf (b1, b4), 14 dpf (b2, b5), and 20 dpf (b3, b6). c Frequency distribution of PGC number at 1 dpf; two boxes with dashed frame label the selected population of “PGC-less” and “PGC-rich.” The lateral areas of gonads were calculated and were shown at the lower right corner of images in a and bd The sex ratio in the population of PGC-less and PGC-rich embryos. e Confocal microscopy of small and big gonads at 20 dpf with Tg(piwil1:egfp-UTRnos3)ihb327Tg transgenic fish. e1 Confocal image of small gonads. e2Higher magnification of a representative image of small gonad displaying combined channels of DAPI, F-actin, and EGFP. e3 Magnification image showing the nuclei of gonocyte in a small gonad. e4 Confocal image of big gonads. e5e6 Higher magnification of representative images of big gonads displaying combined channels of DAPI, F-actin, and EGFP. e5 shows an example in which the germ cells have an irregular shape of nuclei; e6shows an example in which chromatin nucleolus-stage oocytes exist. e7 Magnification image showing cells with irregular shape of nuclei. e8 Magnification image showing that the nuclei of gonocyte were similar to the one in a small gonad

Fig. 3

The abundance of early PGCs promotes female development. a Representative images showing PGCs in wildtype and buc-overexpressed embryos at shield stage (PGCS was visualized by WISH). b Percentage of embryos with increased PGCs or normal number of PGCs in wildtype and buc-overexpressed embryos. c Representative images showing PGCs in wildtype and buc-overexpressed embryos at 1 dpf (PGCS was visualized using Tg(piwil1:egfp-UTRnanos3)ihb327Tg). d The sex ratio in population of wildtype and buc-overexpressed embryos. e RT-qPCR showing that buc was overexpressed in Tg(kop:KalTA4-UTRnanos3,CMV:EGFP)ihb8Tg/Tg(UAS:buc-UTRnanos3)ihb120Tg double-transgenic fish (dual-Tg) and Tg(UAS:buc-UTRnanos3)ihb120Tgf The sex ratio in the populations of sibling control (Tg(kop:KalTA4-UTRnanos3,CMV:EGFP)ihb8Tg and wildtype fish), Tg(UAS:buc-UTRnanos3)ihb120Tg and double transgenics

Acknowledgments:
ZFIN wishes to thank the journal Marine biotechnology (New York, N.Y.) for permission to reproduce figures from this article. Please note that this material may be protected by copyright. Full text @ Mar. Biotechnol.