Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Drosophila Pgc protein inhibits P-TEFb recruitment to chromatin in primordial germ cells

Abstract

Germ cells are the only cells that transmit genetic information to the next generation, and they therefore must be prevented from differentiating inappropriately into somatic cells1. A common mechanism by which germline progenitors are protected from differentiation-inducing signals is a transient and global repression of RNA polymerase II (RNAPII)-dependent transcription1. In both Drosophila and Caenorhabditis elegans embryos, the repression of messenger RNA transcription during germ cell specification correlates with an absence of phosphorylation of Ser 2 residues in the carboxy-terminal domain of RNAPII (hereafter called CTD)2, a critical modification for transcriptional elongation3. Here we show that, in Drosophila embryos, a small protein encoded by polar granule component (pgc) is essential for repressing CTD Ser 2 phosphorylation in newly formed pole cells, the germline progenitors. Ectopic Pgc expression in somatic cells is sufficient to repress CTD Ser 2 phosphorylation. Furthermore, Pgc interacts, physically and genetically, with positive transcription elongation factor b (P-TEFb), the CTD Ser 2 kinase complex, and prevents its recruitment to transcription sites. These results indicate that Pgc is a cell-type-specific P-TEFb inhibitor that has a fundamental role in Drosophila germ cell specification. In C. elegans embryos, PIE-1 protein segregates to germline blastomeres, and is thought to repress mRNA transcription through interaction with P-TEFb4,5,6,7. Thus, inhibition of P-TEFb is probably a common mechanism during germ cell specification in the disparate organisms C. elegans and Drosophila.

This is a preview of subscription content

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: Pgc expression in pole cells is essential for the repression of CTD Ser 2 phosphorylation.
Figure 2: Pgc is sufficient to repress CTD Ser 2 phosphorylation in somatic cells.
Figure 3: Pgc interacts, physically and genetically, with P-TEFb.
Figure 4: Pgc prevents P-TEFb recruitment.

References

  1. 1

    Seydoux, G. & Braun, R. E. Pathway to totipotency: lessons from germ cells. Cell 127, 891–904 (2006)

    CAS  Article  Google Scholar 

  2. 2

    Seydoux, G. & Dunn, M. A. Transcriptionally repressed germ cells lack a subpopulation of phosphorylated RNA polymerase II in early embryos of Caenorhabditis elegans and Drosophila melanogaster . Development 124, 2191–2201 (1997)

    CAS  PubMed  Google Scholar 

  3. 3

    Saunders, A., Core, L. J. & Lis, J. T. Breaking barriers to transcription elongation. Nature Rev. Mol. Cell Biol. 7, 557–567 (2006)

    CAS  Article  Google Scholar 

  4. 4

    Seydoux, G. et al. Repression of gene expression in the embryonic germ lineage of C. elegans . Nature 382, 713–716 (1996)

    CAS  Article  ADS  Google Scholar 

  5. 5

    Mello, C. C. et al. The PIE-1 protein and germline specification in C. elegans embryos. Nature 382, 710–712 (1996)

    CAS  Article  ADS  Google Scholar 

  6. 6

    Batchelder, C. et al. Transcriptional repression by the Caenorhabditis elegans germ-line protein PIE-1. Genes Dev. 13, 202–212 (1999)

    CAS  Article  Google Scholar 

  7. 7

    Zhang, F., Barboric, M., Blackwell, T. K. & Peterlin, B. M. A model of repression: CTD analogs and PIE-1 inhibit transcriptional elongation by P-TEFb. Genes Dev. 17, 748–758 (2003)

    CAS  Article  Google Scholar 

  8. 8

    Nakamura, A., Amikura, R., Mukai, M., Kobayashi, S. & Lasko, P. F. Requirement for a noncoding RNA in Drosophila polar granules for germ cell establishment. Science 274, 2075–2079 (1996)

    CAS  Article  ADS  Google Scholar 

  9. 9

    Martinho, R. G., Kunwar, P. S., Casanova, J. & Lehmann, R. A noncoding RNA is required for the repression of RNApolII-dependent transcription in primordial germ cells. Curr. Biol. 14, 159–165 (2004)

    CAS  Article  Google Scholar 

  10. 10

    Deshpande, G., Calhoun, G. & Schedl, P. Overlapping mechanisms function to establish transcriptional quiescence in the embryonic Drosophila germline. Development 131, 1247–1257 (2004)

    CAS  Article  Google Scholar 

  11. 11

    Shim, E. Y., Walker, A. K., Shi, Y. & Blackwell, T. K. CDK-9/cyclin T (P-TEFb) is required in two postinitiation pathways for transcription in the C. elegans embryo. Genes Dev. 16, 2135–2146 (2002)

    CAS  Article  Google Scholar 

  12. 12

    Ni, Z., Schwartz, B. E., Werner, J., Suarez, J.-R. & Lis, J. T. Coordination of transcription, RNA processing, and surveillance by P-TEFb kinase on heat shock genes. Mol. Cell 13, 55–65 (2004)

    CAS  Article  Google Scholar 

  13. 13

    Peterlin, B. M. & Price, D. H. Controlling the elongation phase of transcription with P-TEFb. Mol. Cell 23, 297–305 (2006)

    CAS  Article  Google Scholar 

  14. 14

    Zhu, Y. et al. Transcription elongation factor P-TEFb is required for HIV-1 Tat transactivation in vitro . Genes Dev. 11, 2622–2632 (1997)

    CAS  Article  Google Scholar 

  15. 15

    Peng, J., Marshall, N. F. & Price, D. H. Identification of a cyclin subunit required for the function of Drosophila P-TEFb. J. Biol. Chem. 273, 13855–13860 (1998)

    CAS  Article  Google Scholar 

  16. 16

    Lis, J. T., Mason, P., Peng, J., Price, D. H. & Werner, J. P-TEFb kinase recruitment and function at heat shock loci. Genes Dev. 14, 792–803 (2000)

    CAS  PubMed  PubMed Central  Google Scholar 

  17. 17

    Eissenberg, J. C., Shilatifard, A., Dorokhov, N. & Michener, D. E. Cdk9 is an essential kinase in Drosophila that is required for heat shock gene expression, histone methylation and elongation factor recruitment. Mol. Genet. Genomics 277, 101–114 (2007)

    CAS  Article  Google Scholar 

  18. 18

    Boehm, A. K., Saunders, A., Werner, J. & Lis, J. T. Transcription factor and polymerase recruitment, modification, and movement on dhsp70 in vivo in the minutes following heat shock. Mol. Cell. Biol. 23, 7628–7637 (2003)

    CAS  Article  Google Scholar 

  19. 19

    Wei, P., Garber, M. E., Fang, S. M., Fischer, W. H. & Jones, K. A. A novel CDK9-associated C-type cyclin interacts directly with HIV-1 Tat and mediates its high-affinity, loop-specific binding to TAR RNA. Cell 92, 451–462 (1998)

    CAS  Article  Google Scholar 

  20. 20

    Barboric, M. & Peterlin, B. M. A new paradigm in eukaryotic biology: HIV Tat and the control of transcriptional elongation. PLoS Biol. 3, e76 (2005)

    Article  Google Scholar 

  21. 21

    Nguyen, V. T., Kiss, T., Michels, A. A. & Bensaude, O. 7SK small nuclear RNA binds to and inhibits the activity of CDK9/cyclin T complexes. Nature 414, 322–325 (2001)

    CAS  Article  ADS  Google Scholar 

  22. 22

    Yang, Z., Zhu, Q., Luo, K. & Zhou, Q. The 7SK small nuclear RNA inhibits the CDK9/cyclin T1 kinase to control transcription. Nature 414, 317–322 (2001)

    CAS  Article  ADS  Google Scholar 

  23. 23

    Michels, A. A. et al. MAQ1 and 7SK RNA interact with CDK9/Cyclin T complexes in a transcription-dependent manner. Mol. Cell. Biol. 23, 4859–4869 (2003)

    CAS  Article  Google Scholar 

  24. 24

    Yik, J. H. N. et al. Inhibition of P-TEFb (CDK9/Cyclin T) kinase and RNA polymerase II transcription by the coordinate action of HEXIM1 and 7SK RNA. Mol. Cell 12, 971–982 (2003)

    CAS  Article  Google Scholar 

  25. 25

    Extavour, C. G. & Akam, M. Mechanisms of germ cell specification across the metazoans: epigenesis and preformation. Development 130, 5869–5884 (2003)

    CAS  Article  Google Scholar 

  26. 26

    Saitou, M., Barton, S. C. & Surani, M. A. A molecular programme for the specification of germ cell fate in mice. Nature 418, 293–300 (2002)

    CAS  Article  ADS  Google Scholar 

  27. 27

    Ohinata, Y. et al. Blimp1 is a critical determinant of the germ cell lineage in mice. Nature 436, 207–213 (2005)

    CAS  Article  ADS  Google Scholar 

  28. 28

    Seki, Y. et al. Cellular dynamics associated with the genome-wide epigenetic reprogramming in migrating primordial germ cells in mice. Development 134, 2627–2638 (2007)

    CAS  Article  Google Scholar 

  29. 29

    Macdonald, P. M. & Struhl, G. Cis-acting sequences responsible for anterior localization of bicoid mRNA in Drosophila embryos. Nature 336, 595–598 (1988)

    CAS  Article  ADS  Google Scholar 

  30. 30

    Spradling, A. C. & Rubin, G. M. Transposition of cloned P elements into Drosophila germ line chromosomes. Science 218, 341–347 (1982)

    CAS  Article  ADS  Google Scholar 

  31. 31

    Larochelle, S., Pandur, J., Fisher, R. P., Salz, H. K. & Suter, B. Cdk7 is essential for mitosis and for in vivo Cdk-activating kinase activity. Genes Dev. 12, 370–381 (1998)

    CAS  Article  Google Scholar 

  32. 32

    Alekseyenko, A. A., Larschan, E., Lai, W. R., Park, P. J. & Kuroda, M. I. High-resolution ChIP-chip analysis reveals that the Drosophila MSL complex selectively identifies active genes on the male X chromosome. Genes Dev. 20, 848–857 (2006)

    CAS  Article  Google Scholar 

  33. 33

    Agata, Y. et al. Histone acetylation determines the developmentally regulated accessibility for T cell receptor γ gene recombination. J. Exp. Med. 193, 873–880 (2001)

    CAS  Article  Google Scholar 

Download references

Acknowledgements

We thank K. Zinn for the lambda phage genomic clone containing the gp150 region, P. Rørth and E. R. Gavis for plasmids, J. T. Lis, D. H. Price and S. Larochelle for antibodies, the Berkeley Drosophila Genome Project and the Bloomington Drosophila stock center for fly stocks, and J. Nakayama, M. Ukai-Tadenuma and H. R. Ueda for technical advice on ChIP analysis. This work was supported in part by a Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology, and Japan Society of the Promotion of Science, Japan and the RIKEN President Discretionary Fund (to A.N.), and by grants from CIHR and NICHD (to P.L.).

Author Contributions K.H.-N., P. L. and A.N. conceived and designed the experiments. K.H.-N., H.S.-N., A T. and A. N. performed the experiments and generated all the figures. P.L. and A.N. wrote the paper.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Akira Nakamura.

Supplementary information

Supplementary Information

The file contains Supplementary Figures 1-10 with Legends, Supplementary Table 1, Supplementary Discussion and additional references. (PDF 3679 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Hanyu-Nakamura, K., Sonobe-Nojima, H., Tanigawa, A. et al. Drosophila Pgc protein inhibits P-TEFb recruitment to chromatin in primordial germ cells. Nature 451, 730–733 (2008). https://doi.org/10.1038/nature06498

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing