In chickens, cryopreservation of primordial germ cells (PGCs), the embryonic precursors of gametes, is the best way to cryobank chicken germplasm. However, as cryoprotectants are yet to be optimized for chicken PGCs, the efficacy of cryomedia can be further improved. Hamai et al. designed dimethyl sulfoxide-based and propylene glycol-based cryomedia in conjunction with trehalose and serum that achieved >50% recovery of viable PGCs after thawing while maintaining germline competency (Hamai et al. Development of cryopreservation media for the slow-freezing of cultured primordial germ cells in chicken, pp. 109–117). The offspring of Kurokashiwa, a rare chicken breed in Japan, was successfully revived from PGCs cryopreserved in this cryomedia.
Nik-related protein kinase (Nrk) is an X-linked gene encoding a serine/threonine kinase belonging to GCK group 4. Nrk-knockout (Nrk-KO) mice exhibit delayed delivery. However, the mechanism of delayed labor remains largely unknown. Yomogita et al. found that serum progesterone (P4) and placental lactogen (PL-2) concentrations during late pregnancy were higher in pregnant females with Nrk-KO conceptus than in wildtype females (Yomogita et al. A possible function of Nik-related kinase in labyrinth layer of mouse placentas of delayed delivery. pp 32–40). These findings suggest that Nrk-KO mice exhibit delayed delivery due to the increase in P4 concentrations because of PL-2 hypersecretion. Moreover, Nrk was expressed in trophoblast giant cells and syncytiotrophoblast-2 (SynT-2) in the labyrinth layer of the mouse placenta. In the human placenta, NRK is expressed in Syn-T of villi. Similar to mouse Nrk, human NRK may significantly affect placentation in evolutionary biology.
NANOS3 is an evolutionarily conserved gene expressed in primordial germ cells, and it is important for germ cell development. Germ cell deletion through NANOS3 knockout has been reported in several mammalian species, although its function in pigs remains unclear. Kogasaka et al. investigated the germline effects of NANOS3 knockout in pigs (Kogasaka et al. Generation of germ cell-deficient pigs by NANOS3 knockout. p. 361–368). Transfer of gene-edited embryos using multiple gRNAs with the Cas9 protein efficiently produced NANOS3-knockout pigs. Histological analysis revealed the lack of germ cells in the testes and ovaries of all NANOS3-knockout pigs. These results demonstrated that NANOS3 is crucial for germ cell production in pigs.
Green Fluorescent Protein as a Novel Vital Marker in Transgenic Mouse
Released on J-STAGE: October 20, 2010 | Volume 43 Issue 6 Pages j19-j25
Masaru OKABE, Masahito IKAWA, Shuichi YAMADA, Tomoko NAKANISHI, Tadashi BABA
Neuroendocrine Mechanisms Regulating Pulsatile Luteinizing Hormone Secretion
Released on J-STAGE: October 20, 2010 | Volume 41 Issue 6 Pages j103-j111
Development of cryopreservation media for the slow-freezing of cultured primordial germ cells in chicken
Released on J-STAGE: April 03, 2023 | Volume 69 Issue 2 Pages 109-117
Natsuko HAMAI, Chihiro KOIDE, Yuki TANSHO, Yukino OOKA, Mayo HIRANO, Effrosyni FATIRA, Masaoki TSUDZUKI, Yoshiaki NAKAMURA
Cell Biological Analysis of the Programmed Cell Death in Limb Morphogenesis
Released on J-STAGE: October 20, 2010 | Volume 42 Issue 6 Pages j127-j133