| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Advances in Brief |
Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| ABSTRACT |
|---|
|
|
|---|
| Introduction |
|---|
|
|
|---|
| Materials and Methods |
|---|
|
|
|---|
Meiotic Preparations.
Meiotic spreads were prepared by standard techniques
(13)
from testes removed from patients suffering
from metastatic prostate cancer or chronic testicular pain, or from
129/BALB mice; indirect immunofluorescence was performed as for
fibroblasts.
Immunofluorescence.
Two days prior to fixation, cells were split at varying dilutions onto
multiwell slides (Cellpoint). Eight h prior to fixation, some slides
were exposed to 10 Gy of IR and then returned to the incubator. WI38
and NBS fibroblasts were grown on the same slide to ensure uniformity
of the culture conditions. Slides were prepared using the CSK and
PFA fixation method as described previously (14
, 15)
. Briefly, slides were washed once in PBS, washed for 30 s in CSK [100 mM NaCl, 300 mM sucrose, 3
mM MgCl2, 10 mM PIPES (pH
6.8)], incubated for 2 min in CSK containing 0.5% Triton X-100,
washed briefly in CSK, and then fixed in PBS containing 4% PFA
(Electron Microscopy Sciences) for 10 min.
Primary antibodies and their dilutions were as follows: rabbit anti-p95 and rabbit anti-MRE11 (gifts of J. Petrini, University of Wisconsin; a subsequent aliquot was the gift of D. Hill, Oncogene Research, Boston, MA), both 1:200 dilutions; mouse monoclonal anti-PML (Santa Cruz), 1:100 dilution; rabbit anti-SCP3 (gift of Christa Heyting), 1:200 dilution; 3H3 mouse anti-SCP3 (gift of Christa Heyting), 1:2 dilution; PX1 mouse anti-MRE11 (GeneTex), 1:50 dilution; mouse anti-TRF1 (gift of Titia deLange, Rockefeller University, NY), 1:5000 dilution. Slides were preincubated in blocking buffer [PBS containing 0.2% cold water fish skin gelatin (Sigma), 5% goat serum, and 0.2% Tween 20] for 30 min and then incubated for 1 h in blocking buffer containing the indicated concentration of primary antibody (or antibodies) at 37°C in a humidity chamber. Slides were then washed three times for 5 min each in PBS containing 0.2% Tween 20 and then incubated in blocking buffer plus secondary antibody. All secondary antibodies were purchased from Vector and were used at 1:100 dilution with the exception of Cy3 antirabbit and Cy3 antimouse, which were purchased from Amersham-Pharmacia and used at 1:200 dilution. Typical results are shown. In all cases, control experiments were performed using each primary alone and both secondaries to verify the results obtained in the double-labeling experiments.
| Results |
|---|
|
|
|---|
|
-irradiation and then fixed
and stained 8 h later for the presence of p95 and PML (Fig. 1B)
-irradiation
apparently causes redistribution of NB-associated p95 from NBs to
larger domains in the nucleus, some of which abut NBs and some of which
do not. Costaining with DAPI does not reveal any obvious relationship
between these larger p95-containing domains and heterochromatic
regions (Fig. 1B)
The localization of MRE11 was also assessed. A fraction of MRE11 also
concentrated in NBs (Fig. 1C)
. In NBS cells, this
focal MRE11 staining was absent, indicating that p95 is
necessary for MRE11 localization to NBs in the absence of DNA damage
(Fig. 1D)
.
p95 and MRE11 Proteins at Meiotic Telomeres.
Localization of p95 and MRE11 was assayed in both mouse and human
meiotic spreads. Immunofluorescence was performed on mouse meiotic
spreads using anti-p95 and a monoclonal antibody (3H3) directed against
SCP3, a proteinaceous component of the presynaptic axial elements that
remains associated with the synaptonemal complex following synapsis
(16)
. p95 labeling was predominantly seen associated with
the very distal ends of the chromosomes (Fig. 2A)
. This labeling was seen in meiotic spreads in late
leptonema, zygonema, and early pachynema (data not shown). To confirm
these results, MRE11 localization was also determined in these
preparations using a commercially available monoclonal antibody against
MRE11 (PX1; GeneTex) and a polyclonal antisera directed against SCP3
(Fig. 2B)
. MRE11 is seen to be concentrated at the ends of
chromosomes, although some chromosomes are also coated by MRE11
protein. We have observed MRE11 present on the synaptonemal complex of
zero to four chromosomes per meiotic spread (Fig. 2B)
. We
typically observe this MRE11 staining in late leptonema, but we do not
know whether it correlates with the precise stage of the spread within
meiosis.
|
| Discussion |
|---|
|
|
|---|
Although NBs have been reported to be sites of accumulation of recently
synthesized RNA (17)
and of DNA replication
(18)
, a full description of their function is lacking.
Several DNA viruses replicate preferentially near NBs, and many of
these viruses encode proteins that disrupt NBs (19
, 20)
.
The recent demonstration that several proteins with roles in DNA
recombination are present in NBs in cells that maintain their telomeres
via a non-telomerase-dependent mechanism (21)
suggests
that NBs may, under some circumstances, play a role in recombination
and in the maintenance of genome stability as well. The data presented
in this work, together with our recent observation that two helicases
of the RecQ family, BLM and RECQL, as well as a mutual interacting
partner, TopoIII
(22)
, are concentrated in NBs
in primary cells, also support this hypothesis. Alternatively, the NBs
may simply act as a reservoir for proteins that translocate and effect
their functions in other locations throughout the cell. The observation
that p95 and MRE11 relocalize in response to DNA damage supports this
notion.
Although MRE11 and RAD50 proteins recently have been shown to be expressed during meiosis (23) , this is the first demonstration that p95 and MRE11 are specifically present on telomeres during this process; moreover, it is the first demonstration of any telomere-associated proteins in mammalian meiosis to our knowledge. Genetic studies in yeast suggest roles for MRE11p, RAD50p, and the p95 homologue Xrs2p in telomere maintenance (11 , 12) . It is possible that some fraction of these proteins usually associates with telomeres in differentiated somatic cells but cannot be visualized because of the high levels of these proteins elsewhere in the nucleus. Alternatively, the presence of these proteins at meiotic telomeres may represent a meiosis-specific function. In yeast, the RAD50p/MRE11p/Xrs2p complex has been proposed to process the ends of chromosomes in mitotic cells, rendering them suitable substrates for telomerase (11) . High levels of telomerase are found in the testes of M. musculus (24) . It is possible that the telomere-associated p95 and MRE11 we observed are responsible for processing the telomeres to a telomerase-accessible form. It will be interesting to study whether these proteins are also associated with telomeres in telomerase-positive somatic stem cells.
| ACKNOWLEDGMENTS |
|---|
| FOOTNOTES |
|---|
1 D. B. L was supported by an MSTP
grant to Harvard Medical School. The Guarente laboratory is supported
by grants from the NIH, The Ellison Medical Foundation, The Seaver
Institute, and The Howard and Linda Stern Foundation. ![]()
2 To whom requests for reprints should be
addressed, at Department of Biology, Massachusetts Institute of
Technology, Cambridge, MA 02139. E-mail: leng{at}mit.edu ![]()
3 The abbreviations used are: NBS, Nijmegen
breakage syndrome; IR, ionizing radiation; NB, nuclear body. ![]()
4 R. S. Maser and J. H. Petrini,
personal communication. ![]()
Received 1/20/00. Accepted 3/20/00.
| REFERENCES |
|---|
|
|
|---|
in somatic and meiotic cells. Cancer Res., 60: 1162-1167, 2000.This article has been cited by other articles:
![]() |
M. H. Luo, K. Rosenke, K. Czornak, and E. A. Fortunato Human Cytomegalovirus Disrupts both Ataxia Telangiectasia Mutated Protein (ATM)- and ATM-Rad3-Related Kinase-Mediated DNA Damage Responses during Lytic Infection J. Virol., February 15, 2007; 81(4): 1934 - 1950. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Yang, J.-H. Jeong, A. L. Brown, C.-H. Lee, P. P. Pandolfi, J. H. Chung, and M. K. Kim Promyelocytic Leukemia Activates Chk2 by Mediating Chk2 Autophosphorylation J. Biol. Chem., September 8, 2006; 281(36): 26645 - 26654. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. J. Luciani, D. Depetris, Y. Usson, C. Metzler-Guillemain, C. Mignon-Ravix, M. J. Mitchell, A. Megarbane, P. Sarda, H. Sirma, A. Moncla, et al. PML nuclear bodies are highly organised DNA-protein structures with a function in heterochromatin remodelling at the G2 phase J. Cell Sci., June 15, 2006; 119(12): 2518 - 2531. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. E. Cohen, S. E. Pollack, and J. W. Pollard Genetic Analysis of Chromosome Pairing, Recombination, and Cell Cycle Control during First Meiotic Prophase in Mammals Endocr. Rev., June 1, 2006; 27(4): 398 - 426. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. J. Chiang, M.-L. Nguyen, S. Gurunathan, P. Kaminker, L. Tessarollo, J. Campisi, and R. J. Hodes Generation and characterization of telomere length maintenance in tankyrase 2-deficient mice. Mol. Cell. Biol., March 1, 2006; 26(6): 2037 - 2043. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. H. Stracker, D. V. Lee, C. T. Carson, F. D. Araujo, D. A. Ornelles, and M. D. Weitzman Serotype-Specific Reorganization of the Mre11 Complex by Adenoviral E4orf3 Proteins J. Virol., June 1, 2005; 79(11): 6664 - 6673. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Eladad, T.-Z. Ye, P. Hu, M. Leversha, S. Beresten, M. J. Matunis, and N. A. Ellis Intra-nuclear trafficking of the BLM helicase to DNA damage-induced foci is regulated by SUMO modification Hum. Mol. Genet., May 15, 2005; 14(10): 1351 - 1365. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. W. Ching, G. Dellaire, C. H. Eskiw, and D. P. Bazett-Jones PML bodies: a meeting place for genomic loci? J. Cell Sci., March 1, 2005; 118(5): 847 - 854. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Nabetani, O. Yokoyama, and F. Ishikawa Localization of hRad9, hHus1, hRad1, and hRad17 and Caffeine-sensitive DNA Replication at the Alternative Lengthening of Telomeres-associated Promyelocytic Leukemia Body J. Biol. Chem., June 11, 2004; 279(24): 25849 - 25857. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Kurki, L. Latonen, and M. Laiho Cellular stress and DNA damage invoke temporally distinct Mdm2, p53 and PML complexes and damage-specific nuclear relocalization J. Cell Sci., October 1, 2003; 116(19): 3917 - 3925. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. R. Davalos and J. Campisi Bloom syndrome cells undergo p53-dependent apoptosis and delayed assembly of BRCA1 and NBS1 repair complexes at stalled replication forks J. Cell Biol., September 29, 2003; 162(7): 1197 - 1209. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. M. Cerosaletti and P. Concannon Nibrin Forkhead-associated Domain and Breast Cancer C-terminal Domain Are Both Required for Nuclear Focus Formation and Phosphorylation J. Biol. Chem., June 6, 2003; 278(24): 21944 - 21951. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Wu, X. Jiang, W.-H. Lee, and P.-L. Chen Assembly of Functional ALT-associated Promyelocytic Leukemia Bodies Requires Nijmegen Breakage Syndrome 1 Cancer Res., May 15, 2003; 63(10): 2589 - 2595. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. de Jager and R. Kanaar Genome instability and Rad50S: subtle yet severe Genes & Dev., September 1, 2002; 16(17): 2173 - 2178. [Full Text] [PDF] |
||||
![]() |
C. F. Bender, M. L. Sikes, R. Sullivan, L. E. Huye, M. M. Le Beau, D. B. Roth, O. K. Mirzoeva, E. M. Oltz, and J. H. J. Petrini Cancer predisposition and hematopoietic failure in Rad50S/S mice Genes & Dev., September 1, 2002; 16(17): 2237 - 2251. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. M. Nakamura, B. A. Moser, and P. Russell Telomere Binding of Checkpoint Sensor and DNA Repair Proteins Contributes to Maintenance of Functional Fission Yeast Telomeres Genetics, August 1, 2002; 161(4): 1437 - 1452. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Hu, S. Beresten, A. van Brabant, T.-Z. Ye, P.-P. Pandolfi, F. B. Johnson, L. Guarente, and N. A. Ellis Evidence for BLM and Topoisomerase III{{alpha}} interaction in genomic stability Hum. Mol. Genet., June 1, 2001; 10(12): 1287 - 1298. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. M. Taylor, J. S. Moghraby, J. H. Lees, B. Smit, P. B. Moens, and A. R. Lehmann Characterization of a Novel Human SMC Heterodimer Homologous to the Schizosaccharomyces pombe Rad18/Spr18 Complex Mol. Biol. Cell, June 1, 2001; 12(6): 1583 - 1594. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. P. Pandolfi Oncogenes and tumor suppressors in the molecular pathogenesis of acute promyelocytic leukemia Hum. Mol. Genet., April 1, 2001; 10(7): 769 - 775. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. de Jager, M. L. G. Dronkert, M. Modesti, C. E. M. T. Beerens, R. Kanaar, and D. C. van Gent DNA-binding and strand-annealing activities of human Mre11: implications for its roles in DNA double-strand break repair pathways Nucleic Acids Res., March 15, 2001; 29(6): 1317 - 1325. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. McIlrath, S. D. Bouffler, E. Samper, A. Cuthbert, A. Wojcik, I. Szumiel, P. E. Bryant, A. C. Riches, A. Thompson, M. A. Blasco, et al. Telomere Length Abnormalities in Mammalian Radiosensitive Cells Cancer Res., February 1, 2001; 61(3): 912 - 915. [Abstract] [Full Text] |
||||
![]() |
O. K. Mirzoeva and J. H. J. Petrini DNA Damage-Dependent Nuclear Dynamics of the Mre11 Complex Mol. Cell. Biol., January 1, 2001; 21(1): 281 - 288. [Abstract] [Full Text] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Cancer Research | Clinical Cancer Research |
| Cancer Epidemiology Biomarkers & Prevention | Molecular Cancer Therapeutics |
| Molecular Cancer Research | Cancer Prevention Research |
| Cancer Prevention Journals Portal | Cancer Reviews Online |
| Annual Meeting Education Book | Cell Growth & Differentiation |