Related Experiment Video
Updated: Jul 16, 2026
Quantitative Analysis of Protein Expression to Study Lineage Specification in Mouse Preimplantation Embryos
Published on: February 22, 2016
Analysis of Ppp1cc-null mice suggests a role for PP1gamma2 in sperm morphogenesis
Rumela Chakrabarti1, Douglas Kline, Jing Lu
1Department of Biological Sciences, Kent State University, Kent, OH 44242, USA.
Abstract:
Serine/threonine protein phosphatase 1 (PP1) consists of four ubiquitously expressed major isoforms, two of which, PP1gamma1 and PP1gamma2, are derived by alternative splicing of a single gene, Ppp1cc. PP1gamma2 is the most abundant isoform in the testis, and is a key regulator of sperm motility. Targeted disruption of the Ppp1cc gene causes male infertility in mice due to impaired spermiogenesis. This study was undertaken to determine the expression patterns of specific PP1 isoforms in testes of wild-type mice and to establish how the defects produced in Ppp1cc-null developing sperm are related to the loss of PP1gamma isoform expression. We observed that PP1gamma2 was prominently expressed in the cytoplasm of secondary spermatocytes and round spermatids as well as in elongating spermatids and testicular and epididymal spermatozoa, whereas its expression was weak or absent in spermatogonia, pachytene spermatocytes, and interstitial cells. In contrast, a high level of PP1gamma1 expression was observed in interstitial cells, whereas much weaker expression was observed in all stages of spermatogenesis. Another PP1 isoform, PP1alpha, was predominant in spermatogonia, pachytene spermatocytes, and interstitial cells. Examining the temporal expression of PP1 enzymes in testes revealed a striking postnatal increase in PP1gamma2 levels compared with other isoforms. Testicular sperm tails from Ppp1cc-null mice showed malformed mitochondrial sheaths and extra outer dense fibers in both the middle and principal pieces. These data suggest that in addition to its previously documented role in motility, PP1gamma2 is involved in sperm tail morphogenesis.
Insights
The serine/threonine protein phosphatase 1 gamma 2 (PP1gamma2) isoform is crucial for sperm tail development and function. Loss of PP1gamma2 in mice leads to impaired sperm structure and male infertility.
Area of Science:
- Reproductive Biology
- Molecular Cell Biology
- Biochemistry
Background:
- Serine/threonine protein phosphatase 1 (PP1) has four major isoforms.
- PP1gamma1 and PP1gamma2 are derived from the Ppp1cc gene.
- PP1gamma2 is vital for sperm motility and its absence causes male infertility in mice.
Purpose of the Study:
- To investigate PP1 isoform expression in wild-type mouse testes.
- To correlate Ppp1cc gene defects with PP1gamma isoform loss in developing sperm.
- To understand PP1gamma2's role in sperm tail morphogenesis.
Main Methods:
- Analysis of PP1 isoform expression patterns in wild-type mouse testes.
- Examination of testicular sperm from Ppp1cc-null mice.
- Assessment of temporal expression of PP1 enzymes during postnatal development.
Main Results:
- PP1gamma2 is highly expressed in mature sperm and developing spermatids, but not in early spermatogenic cells.
- PP1gamma1 is mainly found in interstitial cells, with minimal expression in spermatogenesis.
- PP1alpha is predominant in spermatogonia, pachytene spermatocytes, and interstitial cells.
- Ppp1cc-null mouse sperm exhibit malformed mitochondrial sheaths and abnormal outer dense fibers.
Conclusions:
- PP1gamma2 plays a significant role in sperm tail morphogenesis, beyond its known function in motility.
- Altered PP1gamma2 expression impacts sperm tail structure, contributing to infertility.
