Identification of various testicular cell populations in pubertal and adult cockerels

Authors: MUCKSOVA, J - BIOPHERM CZECH REPUBLIC; BRILLARD, J - MONNAIE FRANCE; HEJNAR, J - CZECH REPUBLIC; POPLSTEIN, M - BIOPHERM CZECH REPUBLIC; KALINA, J - BIOPHERM CZECH REPUBLIC; Bakst, Murray; YAN, H - HIAVS QUANTANG CHINA; TREFIL, P - HIAVS QUANTANG CHINA

Submitted to: Animal Reproduction Science
Publication Type: Abstract Only
Publication Acceptance Date: 10/13/2008
Publication Date: 6/1/2009
Citation: Mucksova, J., Brillard, J.P., Hejnar, J., Poplstein, M., Kalina, J., Bakst, M.R., Yan, H., Trefil, P. 2009. Identification of various testicular cell populations in pubertal and adult cockerels. Animal Reproduction Sciences, 114:415-422.

Interpretive Summary: Transgenic chicken and turkey production can be accomplished by transferring donor testicular stem cells carrying a transgene to recipient sterile males. The sperm produced in the recipient males will then introduce the new transgene into the ovum at fertilization and the resulting and the chick or poult would express that new gene. The identification and isolation of the donor testicular stem cells is a difficult task. In this study we describe a method that identifies proteins expressed on the surface of the donor testicular stem cells and allows us to separate these cells from the rest of the testicular cells. In doing this, a side population cells were isolated and believed to contain the testicular stem cells. This work will benefit scientists investigating semen production in poultry, a novel approach to germplasm preservation, and transgenic bird production. The technology will make transgenic bird production available to the poultry and pharmaceutical industries.

Technical Abstract: Precise identification of the male germinal stem cell population is important for their practical use in programs dedicated to the integration of exogenous genetic material in testicular tissues. In the present study, our aim was to identify germinal cell populations in the testes of pubertal and adult cockerels based on the detection of the nuclear DNA content by fluorescence-activated cell sorting (FACS) and on the expression of the Dazl and Stra8 genes in single cell suspensions of testicular tissues. Cells with a tetraploid DNA content (4c) represent a small and equal fraction of the total germinal cell population in both pubertal and adult males. In contrast, the diploid (2c) and haploid (c) subpopulations differ significantly between ages as a consequence of different degrees of sexual maturation. A specific subpopulation of testicular cells, the side-scatter subpopulation of cells, or side population (SP), was identified at the junction between the haploid and diploid cell populations. The percentage of this cell subpopulation differs significantly in pubertal and adult cockerels, accounting for 4.1% and 1.3% of the total cell population, respectively. These four testicular cell populations were also tested for the expression of Dazl and Stra8 genes known to be expressed in premeiotic cells including stem spermatogonia. Both genes were expressed in SP, whereas the expression of either Dazl or Stra8 genes was detected only in the 4 and in the 2c testicular cell subpopulations, respectively. The correlation between the cell ploidy and Dazl and Stra8 expression was the same at both male ages. We conclude that SP cells might represent a subpopulation of germinal cells enriched in stem spermatogonia, which can be of great importance for transgenesis in chicken.