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Published on: January 14, 2021
Analysis of CREM-dependent gene expression during mouse spermatogenesis
Tim Beissbarth1, Igor Borisevich, Andreas Hörlein
1Molecular Biology of the Cell 1, German Cancer Research Center, DKFZ, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany. tim.beissbarth@molgen.mpg.de
Abstract:
The transcription factors CREM, CREB, and ATF-1 constitute a subfamily of beta-Zip transcription factors. Several different kinase cascades regulate the activity of these proteins. The activator splice-isoform CREMtau is specifically and highly expressed in post-meiotic germ cells during mouse spermatogenesis. Male mice lacking CREMtau expression are sterile because of stage-specific arrest of sperm maturation as the spermatids undergo apoptosis. In order to characterize the genes that are controlled by CREM during post-meiotic differentiation of round spermatids, we compared the expression levels of mRNA prepared from testes of wild-type and CREM-deficient mice by suppression subtractive hybridization (SSH) and affymetrix oligonucleotide arrays. A set of 956 unique sequences found in the CREM SSH library was further characterized by generating stage-specific expression profiles during spermatogenesis by hybridization with cDNA from pre-pubertal mice at defined stages of spermatogenesis using nylon DNA arrays. The resulting expression profiles were arranged in a linear order according to similarity in their profile shapes to find co-regulation of functionally related genes. Our data shows that a large number of genes are transcriptionally activated in round spermatids when CREM activity is maximal, including functional groups like transcription factors, proteins involved in signal transduction, and metabolic enzymes, therefore providing novel information of post-meiotic expression of many known as well as novel genes that are either directly or indirectly influenced by CREM expression.
Insights
The cAMP response element modulator (CREM) transcription factor is crucial for male fertility. Its absence causes sterility due to germ cell apoptosis, highlighting CREM's role in sperm maturation.
Area of Science:
- Reproductive Biology
- Molecular Endocrinology
- Gene Regulation
Background:
- CREM, CREB, and ATF-1 are beta-Zip transcription factors regulating gene expression.
- CREMtau, an activator splice-isoform, is vital for mouse spermatogenesis.
- CREMtau deficiency leads to male sterility via spermatid apoptosis.
Purpose of the Study:
- To identify genes regulated by CREM during post-meiotic germ cell differentiation.
- To understand the molecular mechanisms underlying CREM-mediated spermatogenesis.
Main Methods:
- Suppression subtractive hybridization (SSH) to compare gene expression in wild-type and CREM-deficient mouse testes.
- Affymetrix oligonucleotide arrays and nylon DNA arrays for detailed expression profiling.
- Analysis of stage-specific expression patterns to identify co-regulated gene networks.
Main Results:
- Identified 956 unique sequences regulated by CREM.
- Revealed significant transcriptional activation of numerous genes in round spermatids when CREM activity is maximal.
- Discovered CREM influences functional groups including transcription factors, signal transduction proteins, and metabolic enzymes.
Conclusions:
- CREM plays a critical role in the transcriptional control of post-meiotic gene expression during spermatogenesis.
- Provides novel insights into genes directly and indirectly influenced by CREM.
- Establishes CREM as a key regulator of male germ cell differentiation and fertility.
