![]() |
|
|
A more recent version of this article appeared on January 1, 2006
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Submitted on June 20, 2005
Revised on September 15, 2005
Accepted on October 5, 2005

*Department of Public Health and Cell Biology, Section of Anatomy and
Department of Biology, University of Rome "Tor Vergata," 00133 Rome, Italy;
Institute of Experimental Neuroscience, Fondazione Santa Lucia IRCCS, 00179 Rome, Italy
Monitoring Editor: Joseph Gall
Translational control plays a crucial role during gametogenesis in organisms as different as worms and mammals. Mouse knock-out models have highlighted the essential function of many RNA-binding proteins during spermatogenesis. Herein we have investigated the expression and function during mammalian male meiosis of Sam68, an RNA-binding protein implicated in several aspects of RNA metabolism. Sam68 expression and localization within the cells is stage specific: it is expressed in the nucleus of spermatogonia, it disappears at the onset of meiosis (leptotene/zygotene stages), and it accumulates again in the nucleus of pachytene spermatocytes and round spermatids. During the meiotic divisions, Sam68 translocates to the cytoplasm where it is found associated with the polysomes. Translocation correlates with serine/threonine phosphorylation and it is blocked by inhibitors of the mitogen activated protein kinases ERK1/2 and of the maturation promoting factor cyclinB-cdc2 complex. Both kinases associate with Sam68 in pachytene spermatocytes and phosphorylate the regulatory regions upstream and downstream of the Sam68 RNA-binding motif. Molecular cloning of the mRNAs associated with Sam68 in mouse spermatocytes reveals a subset of genes that might be post-transcriptionally regulated by this RNA-binding protein during spermatogenesis. We also demonstrate that Sam68 shuttles between the nucleus and the cytoplasm in secondary spermatocytes, suggesting that it may promote translation of specific RNA targets during the meiotic divisions.
This article has been cited by other articles:
![]() |
R. Busa, R. Geremia, and C. Sette Genotoxic stress causes the accumulation of the splicing regulator Sam68 in nuclear foci of transcriptionally active chromatin Nucleic Acids Res., January 27, 2010; (2010): gkq004v1 - gkq004. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Sette, V. Messina, and M. P. Paronetto Sam68: A New STAR in the Male Fertility Firmament J Androl, January 1, 2010; 31(1): 66 - 74. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Ewen, M. Baker, D. Wilhelm, R. J. Aitken, and P. Koopman Global Survey of Protein Expression during Gonadal Sex Determination in Mice Mol. Cell. Proteomics, December 1, 2009; 8(12): 2624 - 2641. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. P. Paronetto, V. Messina, E. Bianchi, M. Barchi, G. Vogel, C. Moretti, F. Palombi, M. Stefanini, R. Geremia, S. Richard, et al. Sam68 regulates translation of target mRNAs in male germ cells, necessary for mouse spermatogenesis J. Cell Biol., April 20, 2009; 185(2): 235 - 249. [Abstract] [Full Text] [PDF] |
||||
![]() |
M.-E. Huot, C. M. Brown, N. Lamarche-Vane, and S. Richard An Adaptor Role for Cytoplasmic Sam68 in Modulating Src Activity during Cell Polarization Mol. Cell. Biol., April 1, 2009; 29(7): 1933 - 1943. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Bianchini, M. Loiarro, P. Bielli, R. Busa, M. P. Paronetto, F. Loreni, R. Geremia, and C. Sette Phosphorylation of eIF4E by MNKs supports protein synthesis, cell cycle progression and proliferation in prostate cancer cells Carcinogenesis, December 1, 2008; 29(12): 2279 - 2288. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. Ehrmann, C. Dalgliesh, A. Tsaousi, M. P. Paronetto, B. Heinrich, R. Kist, P. Cairns, W. Li, C. Mueller, M. Jackson, et al. Haploinsufficiency of the germ cell-specific nuclear RNA binding protein hnRNP G-T prevents functional spermatogenesis in the mouse Hum. Mol. Genet., September 15, 2008; 17(18): 2803 - 2818. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Smida, A. Posevitz-Fejfar, V. Horejsi, B. Schraven, and J. A. Lindquist A novel negative regulatory function of the phosphoprotein associated with glycosphingolipid-enriched microdomains: blocking Ras activation Blood, July 15, 2007; 110(2): 596 - 625. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. P. Paronetto, T. Achsel, A. Massiello, C. E. Chalfant, and C. Sette The RNA-binding protein Sam68 modulates the alternative splicing of Bcl-x J. Cell Biol., March 26, 2007; 176(7): 929 - 939. [Abstract] [Full Text] [PDF] |
||||