Limits...
MicroRNA biogenesis is required for mouse primordial germ cell development and spermatogenesis.

Hayashi K, Chuva de Sousa Lopes SM, Kaneda M, Tang F, Hajkova P, Lao K, O'Carroll D, Das PP, Tarakhovsky A, Miska EA, Surani MA - PLoS ONE (2008)

Bottom Line: During development of germ cells, miR-17-92 cluster, which is thought to promote cell cycling, and the ES cell-specific cluster encoding miR-290 to -295 (miR-290-295 cluster) were highly expressed in primordial germ cells (PGCs) and spermatogonia.A set of miRNAs was developmentally regulated.Consistently, miRNAs promoting cell cycling are highly expressed in PGCs and spermatogonia.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust/Cancer Research United Kingdom Gurdon Institute, University of Cambridge, Cambridge, United Kingdom.

ABSTRACT

Background: MicroRNAs (miRNAs) are critical regulators of transcriptional and post-transcriptional gene silencing, which are involved in multiple developmental processes in many organisms. Apart from miRNAs, mouse germ cells express another type of small RNA, piwi-interacting RNAs (piRNAs). Although it has been clear that piRNAs play a role in repression of retrotransposons during spermatogenesis, the function of miRNA in mouse germ cells has been unclear.

Methodology/principal findings: In this study, we first revealed the expression pattern of miRNAs by using a real-time PCR-based 220-plex miRNA expression profiling method. During development of germ cells, miR-17-92 cluster, which is thought to promote cell cycling, and the ES cell-specific cluster encoding miR-290 to -295 (miR-290-295 cluster) were highly expressed in primordial germ cells (PGCs) and spermatogonia. A set of miRNAs was developmentally regulated. We next analysed function of miRNA biogenesis in germ cell development by using conditional Dicer-knockout mice in which Dicer gene was deleted specifically in the germ cells. Dicer-deleted PGCs and spermatogonia exhibited poor proliferation. Retrotransposon activity was unexpectedly suppressed in Dicer-deleted PGCs, but not affected in the spermatogonia. In Dicer-deleted testis, spermatogenesis was retarded at an early stage when proliferation and/or early differentiation. Additionally, we analysed spermatogenesis in conditional Argonaute2-deficient mice. In contrast to Dicer-deficient testis, spermatogenesis in Argonaute2-deficient testis was indistinguishable from that in wild type.

Conclusion/significance: These results illustrate that miRNAs are important for the proliferation of PGCs and spermatogonia, but dispensable for the repression of retrotransposons in developing germ cells. Consistently, miRNAs promoting cell cycling are highly expressed in PGCs and spermatogonia. Furthermore, based on normal spermatogenesis in Argonaute2-deficient testis, the critical function of Dicer in spermatogenesis is independent of Argonaute2.

Show MeSH

Related in: MedlinePlus

The miRNA expression during PGC development.(A) High expression of miR-17-92 and miR-290-295 clusters. The miRNA levels detected by real-time PCR are represented as a heat map. The intensity of yellow scale corresponds to the level of miRNA expression; black indicates that expression was undetectable. MiRNAs encoded in miR-17-92 and miR-290-295 clusters are marked with red and blue, respectively. (B-D) Alteration of miRNA expression during PGC development. The relative values of miRNA expression in male (solid line and open cycles) and female (broken line and closed circles) after E12.5 are shown. Until E11.5, the sex of PGCs was not determined. Relative values were calculated by dividing the raw value of the individual miRNA by that of the recombinant miR-16 as its levels were pre-determined in the samples.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2254191&req=5

pone-0001738-g001: The miRNA expression during PGC development.(A) High expression of miR-17-92 and miR-290-295 clusters. The miRNA levels detected by real-time PCR are represented as a heat map. The intensity of yellow scale corresponds to the level of miRNA expression; black indicates that expression was undetectable. MiRNAs encoded in miR-17-92 and miR-290-295 clusters are marked with red and blue, respectively. (B-D) Alteration of miRNA expression during PGC development. The relative values of miRNA expression in male (solid line and open cycles) and female (broken line and closed circles) after E12.5 are shown. Until E11.5, the sex of PGCs was not determined. Relative values were calculated by dividing the raw value of the individual miRNA by that of the recombinant miR-16 as its levels were pre-determined in the samples.

Mentions: Amongst the miRNAs detected in the samples, miRNAs belonging to miR-17-92 cluster was highly expressed in PGCs. All miRNAs, in miR-17-92 cluster except for miR-17-3p were amongst the top twenty highly expressed miRNAs (Figure 1A and Figure S2), but miR-17-3p was undetectable (Figure 1A). The expression levels of miRNAs were maintained throughout development of PGCs, although the expression of some miRNAs (miR-17-5p, -18, -19a and -19b) decreased gradually in female PGCs after E12.5 when they prepare to enter into meiotic prophase. (Figure 1B). Since miR-17-92 cluster promotes cell survival and proliferation in mammalian cancer cells [30], [31], it is possible that miR-17-92 cluster may play a role in promoting the survival and/or the proliferation of PGCs.


MicroRNA biogenesis is required for mouse primordial germ cell development and spermatogenesis.

Hayashi K, Chuva de Sousa Lopes SM, Kaneda M, Tang F, Hajkova P, Lao K, O'Carroll D, Das PP, Tarakhovsky A, Miska EA, Surani MA - PLoS ONE (2008)

The miRNA expression during PGC development.(A) High expression of miR-17-92 and miR-290-295 clusters. The miRNA levels detected by real-time PCR are represented as a heat map. The intensity of yellow scale corresponds to the level of miRNA expression; black indicates that expression was undetectable. MiRNAs encoded in miR-17-92 and miR-290-295 clusters are marked with red and blue, respectively. (B-D) Alteration of miRNA expression during PGC development. The relative values of miRNA expression in male (solid line and open cycles) and female (broken line and closed circles) after E12.5 are shown. Until E11.5, the sex of PGCs was not determined. Relative values were calculated by dividing the raw value of the individual miRNA by that of the recombinant miR-16 as its levels were pre-determined in the samples.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2254191&req=5

pone-0001738-g001: The miRNA expression during PGC development.(A) High expression of miR-17-92 and miR-290-295 clusters. The miRNA levels detected by real-time PCR are represented as a heat map. The intensity of yellow scale corresponds to the level of miRNA expression; black indicates that expression was undetectable. MiRNAs encoded in miR-17-92 and miR-290-295 clusters are marked with red and blue, respectively. (B-D) Alteration of miRNA expression during PGC development. The relative values of miRNA expression in male (solid line and open cycles) and female (broken line and closed circles) after E12.5 are shown. Until E11.5, the sex of PGCs was not determined. Relative values were calculated by dividing the raw value of the individual miRNA by that of the recombinant miR-16 as its levels were pre-determined in the samples.
Mentions: Amongst the miRNAs detected in the samples, miRNAs belonging to miR-17-92 cluster was highly expressed in PGCs. All miRNAs, in miR-17-92 cluster except for miR-17-3p were amongst the top twenty highly expressed miRNAs (Figure 1A and Figure S2), but miR-17-3p was undetectable (Figure 1A). The expression levels of miRNAs were maintained throughout development of PGCs, although the expression of some miRNAs (miR-17-5p, -18, -19a and -19b) decreased gradually in female PGCs after E12.5 when they prepare to enter into meiotic prophase. (Figure 1B). Since miR-17-92 cluster promotes cell survival and proliferation in mammalian cancer cells [30], [31], it is possible that miR-17-92 cluster may play a role in promoting the survival and/or the proliferation of PGCs.

Bottom Line: During development of germ cells, miR-17-92 cluster, which is thought to promote cell cycling, and the ES cell-specific cluster encoding miR-290 to -295 (miR-290-295 cluster) were highly expressed in primordial germ cells (PGCs) and spermatogonia.A set of miRNAs was developmentally regulated.Consistently, miRNAs promoting cell cycling are highly expressed in PGCs and spermatogonia.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust/Cancer Research United Kingdom Gurdon Institute, University of Cambridge, Cambridge, United Kingdom.

ABSTRACT

Background: MicroRNAs (miRNAs) are critical regulators of transcriptional and post-transcriptional gene silencing, which are involved in multiple developmental processes in many organisms. Apart from miRNAs, mouse germ cells express another type of small RNA, piwi-interacting RNAs (piRNAs). Although it has been clear that piRNAs play a role in repression of retrotransposons during spermatogenesis, the function of miRNA in mouse germ cells has been unclear.

Methodology/principal findings: In this study, we first revealed the expression pattern of miRNAs by using a real-time PCR-based 220-plex miRNA expression profiling method. During development of germ cells, miR-17-92 cluster, which is thought to promote cell cycling, and the ES cell-specific cluster encoding miR-290 to -295 (miR-290-295 cluster) were highly expressed in primordial germ cells (PGCs) and spermatogonia. A set of miRNAs was developmentally regulated. We next analysed function of miRNA biogenesis in germ cell development by using conditional Dicer-knockout mice in which Dicer gene was deleted specifically in the germ cells. Dicer-deleted PGCs and spermatogonia exhibited poor proliferation. Retrotransposon activity was unexpectedly suppressed in Dicer-deleted PGCs, but not affected in the spermatogonia. In Dicer-deleted testis, spermatogenesis was retarded at an early stage when proliferation and/or early differentiation. Additionally, we analysed spermatogenesis in conditional Argonaute2-deficient mice. In contrast to Dicer-deficient testis, spermatogenesis in Argonaute2-deficient testis was indistinguishable from that in wild type.

Conclusion/significance: These results illustrate that miRNAs are important for the proliferation of PGCs and spermatogonia, but dispensable for the repression of retrotransposons in developing germ cells. Consistently, miRNAs promoting cell cycling are highly expressed in PGCs and spermatogonia. Furthermore, based on normal spermatogenesis in Argonaute2-deficient testis, the critical function of Dicer in spermatogenesis is independent of Argonaute2.

Show MeSH
Related in: MedlinePlus