Andrea Panza - Academia.edu (original) (raw)

Papers by Andrea Panza

Keywords: telomeres ; TERRA ; telomerase ; senescence ; survivors ; telomere deprotection ; check... more Keywords: telomeres ; TERRA ; telomerase ; senescence ; survivors ; telomere deprotection ; checkpoint ; ratl-1 ; cdc13-1 ; stn1-13 ; ku70[Delta] ; mec1[Delta] ; tel1[Delta] ; rad9[Delta] ; est2[Delta] These Ecole polytechnique federale de Lausanne EPFL, n° 5353 (2012)Programme doctoral Approches moleculaires du vivantFaculte des sciences de la vieInstitut suisse de Recherche Experimentale sur le Cancer Unite du Prof. Lingner Reference doi:10.5075/epfl-thesis-5353Print copy in library catalog Record created on 2012-03-08, modified on 2017-05-12

Genetics, Jun 1, 2006

14-3-3 proteins are highly conserved polypeptides that participate in many biological processes b... more 14-3-3 proteins are highly conserved polypeptides that participate in many biological processes by binding phosphorylated target proteins. The Saccharomyces cerevisiae BMH1 and BMH2 genes, whose concomitant deletion is lethal, encode two functionally redundant 14-3-3 isoforms. To gain insights into the essential function(s) shared by these proteins, we searched for high-dosage suppressors of the growth defects of temperature-sensitive bmh mutants. Both the protein kinase C1 (Pkc1) and its upstream regulators Wsc2 and Mid2 were found to act as high dosage suppressors of bmh mutants' temperature sensitivity, indicating a functional interaction between 14-3-3 and Pkc1. Consistent with a role of 14-3-3 proteins in Pkc1-dependent cellular processes, shift to the restrictive temperature of bmh mutants severely impaired initiation of DNA replication, polarization of the actin cytoskeleton, and budding, as well as cell wall integrity. Because Pkc1 acts in concert with the Swi4-Swi6 (SBF) transcriptional activator to control all these processes, the defective G 1 /S transition of bmh mutants might be linked to impaired SBF activity. Indeed, the levels of the G 1 cyclin CLN2 transcripts, which are positively regulated by SBF, were dramatically reduced in bmh mutants. Remarkably, budding and DNA replication defects of bmh mutants were suppressed by CLN2 expression from an SBF-independent promoter, suggesting that 14-3-3 proteins might contribute to regulating the late G 1 transcriptional program.

Molecular and Cellular Biology, May 1, 2007

The highly conserved 14-3-3 proteins participate in many biological processes in different eukary... more The highly conserved 14-3-3 proteins participate in many biological processes in different eukaryotes. The BMH1 and BMH2 genes encode the two functionally redundant Saccharomyces cerevisiae 14-3-3 isoforms. In this work we provide evidence that defective 14-3-3 functions not only impair the ability of yeast cells to sustain DNA replication in the presence of sublethal concentrations of methyl methanesulfonate (MMS) or hydroxyurea (HU) but also cause S-phase checkpoint hyperactivation. Inactivation of the catalytic subunit of the histone acetyltransferase NuA4 or of its interactor Yng2, besides leading to S-phase defects and persistent checkpoint activation in the presence of genotoxic agents, is lethal for bmh mutants. Conversely, the lack of the histone deacetylase subunit Rpd3 or Sin3 partially suppresses the hypersensitivity to HU of bmh mutants and restores their ability to complete DNA replication in the presence of MMS or HU. These data strongly suggest that reduced acetyltransferase functionality might account for the S-phase defects of bmh mutants in the presence of genotoxic agents. Consistent with a role of 14-3-3 proteins in acetyltransferase and deacetylase regulation, we find that acetylation of H3 and H4 histone tails is reduced in temperature-sensitive bmh mutants shifted to the restrictive temperature. Moreover, Bmh proteins physically interact, directly or indirectly, with the Esa1 acetyltransferase throughout the cell cycle and with the Rpd3 deacetylase specifically during unperturbed S phase and after HU treatment. Taken together, our results highlight a novel role for 14-3-3 proteins in the regulation of histone acetyltransferase and deacetylase functions in the response to replicative stress.

FEBS Letters, Jul 23, 2010

Telomeres are heterochromatic structures at the ends of eukaryotic chromosomes. As other heteroch... more Telomeres are heterochromatic structures at the ends of eukaryotic chromosomes. As other heterochromatin regions, telomeres are transcribed, from the subtelomeric region towards chromosome ends into the long non-coding RNA TERRA. Telomere transcription is a widespread phenomenon as it has been observed in species belonging to several kingdoms of the eukaryotic domain. TERRA is part of telomeric heterochromatin in addition to being present in the nucleoplasm. Here, we review the current knowledge of TERRA structure, biogenesis and turnover. In addition, we discuss presumed roles of this RNA during replication of telomeric DNA, heterochromatin formation and the regulation of telomerase.

DNA manipulations and plasmids Standard procedures were used for recombinant DNA manipulations (A... more DNA manipulations and plasmids Standard procedures were used for recombinant DNA manipulations (Ausubel et al., 1991). Yeast genomic DNA was prepared using the Wizard genomic DNA purification kit (Promega). Telomere PCR was performed as previously described (Forstemann et al., 2000). All yeast galactose over-expression plasmids were ordered from Open-biosystems. Purification of polyadenylated RNAs from total RNA 80μg of total RNA isolated from WT or rat1-1 cells was processed following the Oligotex Handbook from Qiagen. The elution was done twice with 40µl elution buffer at 70°C. Southern blot analysis DNA was extracted from 15 OD units of overnight cultures using the Wizard Genomic DNA purification kit (Promega). 25µg DNA was digested with XhoI over-night at 37°C. 10µg were loaded on 1.2 % agarose gels in TBE1x and run over-night at 30V till the size marker 600bp (from the Eurogentec SMART ladder) reached 2cm 2 from the bottom of the gel. Gels were transferred on Hybond N+ membrane...

European Journal of Cancer Supplements, 2008

Molecular Cell, 2008

Vertebrate telomeres are transcribed into telomeric repeat-containing RNA (TERRA) that associates... more Vertebrate telomeres are transcribed into telomeric repeat-containing RNA (TERRA) that associates with telomeres and may be important for telomere function. Here, we demonstrate that telomeres are also transcribed in Saccharomyces cerevisiae by RNA polymerase II (RNAPII). Yeast TERRA is polyadenylated and stabilized by Pap1p and regulated by the 5 0 to 3 0 exonuclease, Rat1p. rat1-1 mutant cells accumulate TERRA and harbor short telomeres because of defects in telomerase-mediated telomere elongation. Overexpression of RNaseH overcomes telomere elongation defects in rat1-1 cells, indicating that RNA/DNA hybrids inhibit telomerase function at chromosome ends in these mutants. Thus, telomeric transcription combined with Rat1p-dependent TERRA degradation is important for regulating telomerase in yeast. Telomere transcription is conserved in different kingdoms of the eukaryotic domain.

FEBS Letters, 2010

Telomeres are heterochromatic structures at the ends of eukaryotic chromosomes. As other heteroch... more Telomeres are heterochromatic structures at the ends of eukaryotic chromosomes. As other heterochromatin regions, telomeres are transcribed, from the subtelomeric region towards chromosome ends into the long non‐coding RNA TERRA. Telomere transcription is a widespread phenomenon as it has been observed in species belonging to several kingdoms of the eukaryotic domain. TERRA is part of telomeric heterochromatin in addition to being present in the nucleoplasm. Here, we review the current knowledge of TERRA structure, biogenesis and turnover. In addition, we discuss presumed roles of this RNA during replication of telomeric DNA, heterochromatin formation and the regulation of telomerase.

Genetics, 2006

Genetics, Jun 1, 2006

Molecular and Cellular Biology, May 1, 2007

FEBS Letters, Jul 23, 2010

European Journal of Cancer Supplements, 2008

Molecular Cell, 2008

FEBS Letters, 2010

Telomeres are heterochromatic structures at the ends of eukaryotic chromosomes. As other heteroch... more Telomeres are heterochromatic structures at the ends of eukaryotic chromosomes. As other heterochromatin regions, telomeres are transcribed, from the subtelomeric region towards chromosome ends into the long non‐coding RNA TERRA. Telomere transcription is a widespread phenomenon as it has been observed in species belonging to several kingdoms of the eukaryotic domain. TERRA is part of telomeric heterochromatin in addition to being present in the nucleoplasm. Here, we review the current knowledge of TERRA structure, biogenesis and turnover. In addition, we discuss presumed roles of this RNA during replication of telomeric DNA, heterochromatin formation and the regulation of telomerase.

Genetics, 2006