The relation of germ cell degeneration to modifications of the testicular structure of Plethodontid salamanders

The murine Bmp8a and Bmp8b genes are tightly linked on mouse chromosome 4 and have similar expression during reproduction. Previous studies have shown that targeted mutagenesis of Bmp8b causes male infertility due to germ cell degeneration. To investigate the function of Bmp8a, we have inactivated the gene by homologous recombination. Heterozygous and homozygous Bmp8a mutants reveal normal embryonic and postnatal development. Despite high levels of Bmp8a expression in the deciduum, homozygous mutant females have normal fertility, suggesting that the gene is not essential for female reproduction. Bmp8a and Bmp8b are expressed in similar patterns in male germ cells. Unlike homozygous Bmp8btm1 mutants, homozygous Bmp8atm1 males do not show obvious germ cell defects during the initiation of spermatogenesis. However, germ cell degeneration is observed in 47% of adult homozygous Bmp8atm1 males, establishing a role of Bmp8a in the maintenance of spermatogenesis. A small proportion of the mating homozygous Bmp8atm1 males also show degeneration of the epididymal epithelium, indicating a novel role for BMPs in the control of epididymal function.

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Spermatocyte toxicity of 2-methoxyethanol in vivo and in vitro: Requirement for an intact seminiferous tubule structure for germ cell degeneration

Toxicology in Vitro ◽

10.1016/0887-2333(94)90109-0 ◽

1994 ◽

Vol 8 (6) ◽

pp. 1191-1202 ◽

Cited By ~ 14

Author(s):

W.W. Ku ◽

R.E. Chapin

Keyword(s):

Germ Cell ◽

Seminiferous Tubule ◽

Cell Degeneration ◽

Germ Cell Degeneration

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A MODIFICATION OF THE URODELE TESTIS RESULTING FROM GERM-CELL DEGENERATION

Biological Bulletin ◽

10.2307/1536657 ◽

1925 ◽

Vol 48 (3) ◽

pp. 145-165 ◽

Cited By ~ 8

Author(s):

R. R. HUMPHREY

Keyword(s):

Germ Cell ◽

Cell Degeneration ◽

Germ Cell Degeneration

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Evaluation of degenerating germ cells in normal juvenile mice

Genome ◽

10.1139/g09-059 ◽

2009 ◽

Vol 52 (10) ◽

pp. 891-896 ◽

Cited By ~ 1

Author(s):

Anastassia Trifonova ◽

Peter B. Moens

Keyword(s):

Cell Death ◽

Germ Cell ◽

Germ Cells ◽

Normal Component ◽

Terminal Deoxynucleotidyl Transferase ◽

Electron Microscopic ◽

Cell Degeneration ◽

Novel Approach ◽

Two Generations ◽

Germ Cell Degeneration

Absence of spermiogenesis in mice with meiotic defects complicates the staging of meiotic arrest using light microscopy. Consequently, new methodologies are required to establish accurate relationships among germ cells. In this study, we utilized a novel approach to analyze germ cell degeneration in juvenile mice. We used terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) in combination with meiosis-specific antibodies. Germ cell degeneration is a normal component of early spermatogenesis in juvenile mice. The incidence of germ cell death was monitored at various postnatal ages of mice using the TUNEL assay to quantify the incidence of apoptosis. Cell death occurred predominantly at 15.5 days after birth. It was found that groups of apoptotic cells were apparent in tubules containing two generations of spermatocytes that form in two progressive cohorts. Electron microscopic observations further illustrated that the majority of cells in the first cohort are in late pachytene, while groups of cells in the second cohort can degenerate in early pachytene. The methodology utilized in this study is significant because it allows one to accurately determine the point at which germ cells arrest. Consequently, we believe that these methods can be applied to study animals with meiotic defects that prevent spermiogenesis.

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