RNA synthesis and poly(adenosine diphosphoribosyl) synthetase activity in developing mouse testis

Area of Science:

• Reproductive biology
• Molecular genetics
• Biochemistry

Background:

• Spermatogenesis involves complex transcriptional regulation.
• RNA polymerases I and II transcribe different gene classes.
• Poly(ADP-ribosyl) synthetase (PARS) plays a role in DNA repair and gene regulation.

Purpose of the Study:

• To investigate the activities of RNA polymerase I, RNA polymerase II, and poly(ADP-ribosyl) synthetase during mouse spermatogenesis.
• To correlate enzymatic activities with developmental stages and germ cell types.

Main Methods:

• Isolation of nuclei from mouse testes at different postnatal ages (1, 3, and 8 weeks).
• Measurement of RNA polymerase I, RNA polymerase II, and poly(ADP-ribosyl) synthetase activities.
• Separation of adult mouse germ cells using unit gravity velocity sedimentation.

Main Results:

• RNA polymerase II and poly(ADP-ribosyl) synthetase activities increased with age and spermatogenesis progression.
• RNA polymerase I activity decreased during spermatogenesis.
• Enriched fractions of pachytene and round spermatids showed high RNA polymerase and poly(ADP-ribosyl) synthetase activities.
• Enzymatic activities in aged mouse testes were comparable to 8-week-old mice.

Conclusions:

• Transcriptional events in spermatogenesis are modulated by changes in RNA polymerase activities.
• The inverse relationship between RNA polymerase I and II activities reflects shifts in RNA species during germ cell development.
• Poly(ADP-ribosyl) synthetase activity is developmentally regulated during spermatogenesis.