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Transcriptome analysis of highly purified mouse spermatogenic cell populations: gene expression signatures switch from meiotic-to postmeiotic-related processes at pachytene stage.

da Cruz I, Rodríguez-Casuriaga R, Santiñaque FF, Farías J, Curti G, Capoano CA, Folle GA, Benavente R, Sotelo-Silveira JR, Geisinger A - BMC Genomics (2016)

Bottom Line: Interestingly, we found that a considerable number of genes involved in early as well as late meiotic processes are already on at early meiotic prophase, with a high proportion of them being expressed only for the short time lapse of lepto-zygotene stages.Moreover, we found that a good proportion of the differential gene expression in spermiogenesis corresponds to up-regulation of genes whose expression starts earlier, at pachytene stage; this includes transition protein-and protamine-coding genes, which have long been claimed to switch on during spermiogenesis.In addition, our results afford new insights concerning X chromosome meiotic inactivation and reactivation.

View Article: PubMed Central - PubMed

Affiliation: Department of Genomics, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE), Av. Italia 3318, 11,600, Montevideo, Uruguay.

ABSTRACT

Background: Spermatogenesis is a complex differentiation process that involves the successive and simultaneous execution of three different gene expression programs: mitotic proliferation of spermatogonia, meiosis, and spermiogenesis. Testicular cell heterogeneity has hindered its molecular analyses. Moreover, the characterization of short, poorly represented cell stages such as initial meiotic prophase ones (leptotene and zygotene) has remained elusive, despite their crucial importance for understanding the fundamentals of meiosis.

Results: We have developed a flow cytometry-based approach for obtaining highly pure stage-specific spermatogenic cell populations, including early meiotic prophase. Here we combined this methodology with next generation sequencing, which enabled the analysis of meiotic and postmeiotic gene expression signatures in mouse with unprecedented reliability. Interestingly, we found that a considerable number of genes involved in early as well as late meiotic processes are already on at early meiotic prophase, with a high proportion of them being expressed only for the short time lapse of lepto-zygotene stages. Besides, we observed a massive change in gene expression patterns during medium meiotic prophase (pachytene) when mostly genes related to spermiogenesis and sperm function are already turned on. This indicates that the transcriptional switch from meiosis to post-meiosis takes place very early, during meiotic prophase, thus disclosing a higher incidence of post-transcriptional regulation in spermatogenesis than previously reported. Moreover, we found that a good proportion of the differential gene expression in spermiogenesis corresponds to up-regulation of genes whose expression starts earlier, at pachytene stage; this includes transition protein-and protamine-coding genes, which have long been claimed to switch on during spermiogenesis. In addition, our results afford new insights concerning X chromosome meiotic inactivation and reactivation.

Conclusions: This work provides for the first time an overview of the time course for the massive onset and turning off of the meiotic and spermiogenic genetic programs. Importantly, our data represent a highly reliable information set about gene expression in pure testicular cell populations including early meiotic prophase, for further data mining towards the elucidation of the molecular bases of male reproduction in mammals.

No MeSH data available.


Related in: MedlinePlus

Enriched GO categories and differential expression of genes in PS and RS. a. Enriched biological process GO terms of up-regulated genes in the PS population compared to LZ. b. Enriched GO terms of up-regulated genes in RS compared to PS. c. Heat maps of the GO categories “sperm motility” (GO# 003017) and “sperm-egg recognition” (GO# 0035036). High expression levels are indicated in red and low expression levels in green
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Fig5: Enriched GO categories and differential expression of genes in PS and RS. a. Enriched biological process GO terms of up-regulated genes in the PS population compared to LZ. b. Enriched GO terms of up-regulated genes in RS compared to PS. c. Heat maps of the GO categories “sperm motility” (GO# 003017) and “sperm-egg recognition” (GO# 0035036). High expression levels are indicated in red and low expression levels in green

Mentions: GO analysis of the up-regulated genes in PS compared to LZ (LZ/PS) showed enrichment in completely different biological processes. Terms related to reproduction, spermatogenesis, gamete generation, spermatid differentiation and development, fertilization, cilium and flagellum assembly and motility, sperm-egg recognition, and binding of sperm to zona pellucida, were among the most significantly represented GO categories (p < 0.01; Fig. 5a). Basically, the same GO terms were enriched in PS/RS (p < 0.01; Fig. 5b). In this regard, when pathway analysis was performed for each set of DEG, a considerable coincidence (three out of five) was found between PS and RS top canonical pathways, while no overlaps were found with LZ. Besides, four of the top five molecular and cellular functions were shared between PS and RS, while only two were in common with LZ (Additional file 3: Dataset S2).Fig. 5


Transcriptome analysis of highly purified mouse spermatogenic cell populations: gene expression signatures switch from meiotic-to postmeiotic-related processes at pachytene stage.

da Cruz I, Rodríguez-Casuriaga R, Santiñaque FF, Farías J, Curti G, Capoano CA, Folle GA, Benavente R, Sotelo-Silveira JR, Geisinger A - BMC Genomics (2016)

Enriched GO categories and differential expression of genes in PS and RS. a. Enriched biological process GO terms of up-regulated genes in the PS population compared to LZ. b. Enriched GO terms of up-regulated genes in RS compared to PS. c. Heat maps of the GO categories “sperm motility” (GO# 003017) and “sperm-egg recognition” (GO# 0035036). High expression levels are indicated in red and low expression levels in green
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4837615&req=5

Fig5: Enriched GO categories and differential expression of genes in PS and RS. a. Enriched biological process GO terms of up-regulated genes in the PS population compared to LZ. b. Enriched GO terms of up-regulated genes in RS compared to PS. c. Heat maps of the GO categories “sperm motility” (GO# 003017) and “sperm-egg recognition” (GO# 0035036). High expression levels are indicated in red and low expression levels in green
Mentions: GO analysis of the up-regulated genes in PS compared to LZ (LZ/PS) showed enrichment in completely different biological processes. Terms related to reproduction, spermatogenesis, gamete generation, spermatid differentiation and development, fertilization, cilium and flagellum assembly and motility, sperm-egg recognition, and binding of sperm to zona pellucida, were among the most significantly represented GO categories (p < 0.01; Fig. 5a). Basically, the same GO terms were enriched in PS/RS (p < 0.01; Fig. 5b). In this regard, when pathway analysis was performed for each set of DEG, a considerable coincidence (three out of five) was found between PS and RS top canonical pathways, while no overlaps were found with LZ. Besides, four of the top five molecular and cellular functions were shared between PS and RS, while only two were in common with LZ (Additional file 3: Dataset S2).Fig. 5

Bottom Line: Interestingly, we found that a considerable number of genes involved in early as well as late meiotic processes are already on at early meiotic prophase, with a high proportion of them being expressed only for the short time lapse of lepto-zygotene stages.Moreover, we found that a good proportion of the differential gene expression in spermiogenesis corresponds to up-regulation of genes whose expression starts earlier, at pachytene stage; this includes transition protein-and protamine-coding genes, which have long been claimed to switch on during spermiogenesis.In addition, our results afford new insights concerning X chromosome meiotic inactivation and reactivation.

View Article: PubMed Central - PubMed

Affiliation: Department of Genomics, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE), Av. Italia 3318, 11,600, Montevideo, Uruguay.

ABSTRACT

Background: Spermatogenesis is a complex differentiation process that involves the successive and simultaneous execution of three different gene expression programs: mitotic proliferation of spermatogonia, meiosis, and spermiogenesis. Testicular cell heterogeneity has hindered its molecular analyses. Moreover, the characterization of short, poorly represented cell stages such as initial meiotic prophase ones (leptotene and zygotene) has remained elusive, despite their crucial importance for understanding the fundamentals of meiosis.

Results: We have developed a flow cytometry-based approach for obtaining highly pure stage-specific spermatogenic cell populations, including early meiotic prophase. Here we combined this methodology with next generation sequencing, which enabled the analysis of meiotic and postmeiotic gene expression signatures in mouse with unprecedented reliability. Interestingly, we found that a considerable number of genes involved in early as well as late meiotic processes are already on at early meiotic prophase, with a high proportion of them being expressed only for the short time lapse of lepto-zygotene stages. Besides, we observed a massive change in gene expression patterns during medium meiotic prophase (pachytene) when mostly genes related to spermiogenesis and sperm function are already turned on. This indicates that the transcriptional switch from meiosis to post-meiosis takes place very early, during meiotic prophase, thus disclosing a higher incidence of post-transcriptional regulation in spermatogenesis than previously reported. Moreover, we found that a good proportion of the differential gene expression in spermiogenesis corresponds to up-regulation of genes whose expression starts earlier, at pachytene stage; this includes transition protein-and protamine-coding genes, which have long been claimed to switch on during spermiogenesis. In addition, our results afford new insights concerning X chromosome meiotic inactivation and reactivation.

Conclusions: This work provides for the first time an overview of the time course for the massive onset and turning off of the meiotic and spermiogenic genetic programs. Importantly, our data represent a highly reliable information set about gene expression in pure testicular cell populations including early meiotic prophase, for further data mining towards the elucidation of the molecular bases of male reproduction in mammals.

No MeSH data available.


Related in: MedlinePlus