Primordial germ cells (PGCs) are the precursors of adult germ cells, and among the embryonic stem-like cells in the bird embryo, only they can transmit the genetic information to the next generation. Despite the wide range of applications, very little is known about the mechanism that governs primordial germ cell self-renewal and differentiation. As a first step, a team led by researchers from the National Agricultural Research and Innovation Centre compared 12 newly established chicken PGC lines derived from two different chicken breeds, performing CCK-8 proliferation assay. All of the lines were derived from individual embryos.

A significant difference was found among the lines. As microRNAs have been proved to play a key role in the maintenance of pluripotency and the cell cycle regulation of stem cells, a complex miRNA analysis which involved miRNA microarray profiling was performed. It was discovered that miRNAs expressed differently in PGC lines with high proliferation rate, compared to PGC lines with low proliferation rate. Gga-miR-2127 was shown to express differently in female and male cell lines. The microarray analysis also revealed high expression level of the gga-miR-302b-3p strand (member of the miR-302/367 cluster) in slowly proliferating PGC lines compared to the gga-miR-302b-5p strand. It was confirmed that the inhibition of miR-302b-5p significantly increases the doubling time of the examined PGC lines.

In conclusion, gga-miR-181-5p, gga-miR-2127, and members of the gga-miR-302/367 cluster have a dominant role in the regulation of avian primordial germ cell proliferation.

 

(a) The microarray analysis was performed on 4 PGC lines (2 female and 2 male) (Supplementary Tables 2–5). On the microarray, 991 chicken-specific miRNAs, 42 plate controls, and 6 gga-5Sb rRNA probes were placed  (b) The Venn diagram introduces the similarities and differences between the cell lines. (c) Paired -test analysis was conducted between the male (4ZP, FS101) and female (5ZP, FS111) PGC lines by LC Sciences Company.

An overview of the results of LC chicken miRNA microarray analysis

 

Reference
B Lázár, M Anand, R Tóth, EP Várkonyi, K Liptói, E Gocza et al. (2018) Comparison of the MicroRNA Expression Profiles of Male and Female Avian Primordial Germ Cell Lines Stem Cells International doi: 10.1155/2018/1780679 [abstract]

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