Abstract:
:Telomerase is a ribonucleoprotein enzyme that adds telomeric sequence repeats to the ends of linear chromosomes. In vitro, telomerase has been observed to add repeats to a DNA oligonucleotide primer in a processive manner, leading to the postulation of a DNA anchor site separate from the catalytic site of the enzyme. We have substituted photoreactive 5-iododeoxypyrimidines into the DNA oligonucleotide primer d(T4G4T4G4T4G2) and, upon irradiation, obtained cross-links with the anchor site of telomerase from Euplotes aediculatus nuclear extract. No cross-linking occurred with a primer having the same 5' end and a nontelomeric 3' end. These cross-links were shown to be between the DNA primer and (i) a protein moiety of approximately 130 kDa and (ii) U51-U52 of the telomerase RNA. The cross-linked primer could be extended by telomerase in the presence of [alpha-32P]dGTP, thus indicating that the 3' end was bound in the enzyme active site. The locations of the cross-links within the single-stranded primers were 20 to 22 nucleotides upstream of the 3' end, providing a measure of the length of DNA required to span the telomerase active and anchor sites. When the single-stranded primers are aligned with the G-rich strand of a Euplotes telomere, the cross-linked nucleotides correspond to the duplex region. Consistent with this finding, a cross-link to telomerase was obtained by substitution of 5-iododeoxycytidine into the CA strand of the duplex region of telomere analogs. We conclude that the anchor site in the approximately 130-kDa protein can bind duplex as well as single-stranded DNA, which may be critical for its function at chromosome ends. Quantitation of the processivity with single-stranded DNA primers and double-stranded primers with 3' tails showed that only 60% of the primer remains bound after each repeat addition.
journal_name
Mol Cell Bioljournal_title
Molecular and cellular biologyauthors
Hammond PW,Lively TN,Cech TRdoi
10.1128/mcb.17.1.296subject
Has Abstractpub_date
1997-01-01 00:00:00pages
296-308issue
1eissn
0270-7306issn
1098-5549journal_volume
17pub_type
杂志文章abstract::The tissue-specific expression of immunoglobulin genes can be partially explained by a requirement for activating factors found only in B lymphocytes and their derivatives. However, loss of immunoglobulin expression upon fusion of an immunoglobulin-producing myeloma cell with a T lymphoma cell (BW5147) or fibroblast (...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.8.5.1932
更新日期:1988-05-01 00:00:00
abstract::The Ras-RAF-mitogen-activated protein kinase (Ras-RAF-MAPK) pathway is overactive in many cancers and in some developmental disorders. In one of those disorders, namely, Noonan syndrome, nine activating C-RAF mutations cluster around Ser(259), a regulatory site for inhibition by 14-3-3 proteins. We show that these mut...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.01636-09
更新日期:2010-10-01 00:00:00
abstract::Two cDNAs derived from Xenopus laevis calmodulin mRNA have been cloned. Both cDNAs contain the complete protein-coding region and various lengths of untranslated segments. The two cDNAs encode an identical protein but differ from each other by 5% nucleotide substitutions. The 5' and 3' untranslated regions, to the ext...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.4.3.507
更新日期:1984-03-01 00:00:00
abstract::To investigate the mechanisms by which transcription factors invade nucleosomal DNA and replace histones at control elements, we have examined the response of the histone octamer to transcription factor binding in the presence of histone-binding proteins (i.e., nucleosome assembly factors). We found that yeast nucleos...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.15.11.6178
更新日期:1995-11-01 00:00:00
abstract::The murine lambda5-VpreB1 locus encodes two proteins that form part of the pre-B-cell receptor and play a key role in B-lymphocyte development. We have identified a locus control region (LCR) which is responsible for coordinate activation of both genes in pre-B cells. Analysis of mice with single and multiple copies o...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.19.1.671
更新日期:1999-01-01 00:00:00
abstract::Distal intraexon (iE) regulatory elements in 4.1R pre-mRNA govern 3' splice site choice at exon 2 (E2) via nested splicing events, ultimately modulating expression of N-terminal isoforms of cytoskeletal 4.1R protein. Here we explored intrasplicing in other normal and disease gene contexts and found conservation of int...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.05716-11
更新日期:2012-06-01 00:00:00
abstract::The c-Myc oncoprotein (Myc) controls cell fate by regulating gene transcription in association with a DNA-binding partner, Max. While Max lacks a transcription regulatory domain, the N terminus of Myc contains a transcription activation domain (TAD) that recruits cofactor complexes containing the histone acetyltransfe...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.25.23.10220-10234.2005
更新日期:2005-12-01 00:00:00
abstract::Phosphorylation of eukaryotic initiation factor 2 alpha (eIF-2 alpha) is typically associated with stress responses and causes a reduction in protein synthesis. However, we found high phosphorylated eIF-2 alpha (eIF-2 alpha[P]) levels in nonstressed pancreata of mice. Administration of glucose stimulated a rapid depho...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.22.11.3864-3874.2002
更新日期:2002-06-01 00:00:00
abstract::Thyroid hormone (T3) is critical for growth, differentiation, and maintenance of metabolic homeostasis. Mice with a knock-in mutation in the thyroid hormone receptor alpha gene (TRalpha1PV) were created previously to explore the roles of mutated TRalpha1 in vivo. TRalpha1PV is a dominant negative mutant with a framesh...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.02189-06
更新日期:2007-03-01 00:00:00
abstract::The full-length versions of the Ras-specific exchange factors Ras-GRF1 (GRF1) and Ras-GRF2 (GRF2), which are expressed in brain and a restricted number of other organs, possess an ionomycin-dependent activation of Erk mitogen-activated protein kinase activity in 293T cells (C. L. Farnsworth et al., Nature 376:524-527,...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.19.7.4611
更新日期:1999-07-01 00:00:00
abstract::Microtubules in yeast are essential components of the mitotic and meiotic spindles and are essential for nuclear movement during cell division and mating. The relative importance in these processes of the two divergent alpha-tubulin genes of the budding yeast Saccharomyces cerevisiae, TUB1 and TUB3, was examined throu...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.6.11.3722
更新日期:1986-11-01 00:00:00
abstract::Spermatogonial stem cells (SSCs) are unipotent germ cells that are at the foundation of spermatogenesis and male fertility. However, the underlying molecular mechanisms governing SSC stemness and growth properties remain elusive. We have recently identified chromodomain helicase/ATPase DNA binding protein 1-like (Chd1...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.00357-18
更新日期:2019-02-04 00:00:00
abstract::Protein kinase C theta (PKC theta) is unique among PKC isozymes in its translocation to the center of the immune synapse in T cells and its unique downstream signaling. Here we show that the hematopoietic protein tyrosine phosphatase (HePTP) also accumulates in the immune synapse in a PKC theta-dependent manner upon a...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.26.5.1806-1816.2006
更新日期:2006-03-01 00:00:00
abstract::Several eukaryotic transcription factors such as Sp1 or Oct1 contain glutamine-rich domains that mediate transcriptional activation. In human cells, promoter-proximally bound glutamine-rich activation domains activate transcription poorly in the absence of acidic type activators bound at distal enhancers, but synergis...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.20.8.2774-2782.2000
更新日期:2000-04-01 00:00:00
abstract::RNA editing in trypanosomes has been proposed to occur through transesterification or endonuclease cleavage and RNA ligation reactions. Both models involve a chimeric intermediate in which a guide RNA (gRNA) is joined through its 3' oligo(U) tail to an editing site of the corresponding mRNA. Velocity centrifugation of...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.15.6.2925
更新日期:1995-06-01 00:00:00
abstract::The folate receptor type alpha (FR-alpha) is a promising tumor marker and target. Here, we investigate the mechanistic basis for the tumor specificity and vast overexpression of FR-alpha. Among representative FR-alpha-positive (HeLa and JAR) and FR-alpha-negative (MG63, Caki1, and HT3) cell lines, the transcription ra...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.23.6.2202-2212.2003
更新日期:2003-03-01 00:00:00
abstract::Barsoum and Varshavsky (Proc. Natl. Acad. Sci. U.S.A. 80:5330-5334, 1983) suggest that polypeptide mitogens and the mitogenic tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulate gene amplification by related pathways. I demonstrated that TPA and the polypeptide mitogen fibroblast growth factor (FGF) bo...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.5.5.1130
更新日期:1985-05-01 00:00:00
abstract::Previous results of our cDNA microarray analysis to look for genes whose expression level correlates well with in vitro tubulogenesis by NP31 endothelial cells revealed the transcription factor ATF3 known to be responsive to stress such as reactive oxygen species (ROS). Anti-ATF3 small interfering RNA gave an inhibito...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.26.3.1087-1097.2006
更新日期:2006-02-01 00:00:00
abstract::A unique genetic selection was devised at the HIS4 locus to address the mechanism of translation initiation in Saccharomyces cerevisiae and to probe sequence requirements at the normal translational initiator region that might participate in ribosomal recognition of the AUG start codon. The first AUG codon at the 5' e...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.8.7.2955
更新日期:1988-07-01 00:00:00
abstract::Protein kinase activities were measured in Rous sarcoma virus-infected baby hamster kidney (BHK) cells that express v-src (BHK [v-src]) and compared with those of revertant and control BHK cells. We observed about a fivefold-higher tyrosine phosphorylating activity in BHK (v-src) cell extracts, which was due to src bu...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.4.5.973
更新日期:1984-05-01 00:00:00
abstract::A variety of genes, including c-myc, are activated by chemical toxicants in vivo and in vitro. Although enforced c-myc expression induces apoptosis after withdrawing survival factors, it is not clear if activation of the endogenous c-myc gene is an apoptotic signal after toxicant exposure. The renal tubular epithelium...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.17.11.6755
更新日期:1997-11-01 00:00:00
abstract::HO endonuclease-induced double-strand breaks in Saccharomyces cerevisiae can undergo recombination by two distinct and competing pathways. In a plasmid containing a direct repeat, in which one repeat is interrupted by an HO endonuclease cut site, gap repair yields gene conversions while single-strand annealing produce...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.12.3.1292
更新日期:1992-03-01 00:00:00
abstract::Endothelial cells differentiate from mesoderm-derived precursors to initiate the earliest events in vascular development. Although the signaling events that regulate the successive steps of vascular development are known in some detail, the transcriptional processes that regulate the first steps in vasculogenesis are ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.23.16.5680-5691.2003
更新日期:2003-08-01 00:00:00
abstract::The TAR RNA binding Protein, TRBP, inhibits the activity of the interferon-induced protein kinase R (PKR), whereas the PKR activator, PACT, activates its function. TRBP and PACT also bind to each other through their double-stranded RNA binding domains (dsRBDs) and their Medipal domains, which may influence their activ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.01030-08
更新日期:2009-01-01 00:00:00
abstract::The human neuroblastoma cell line CHP100 provides a useful model system in which to study the molecular mechanisms of transcriptional regulation of the low-affinity nerve growth factor receptor (NGFR) gene during neuronal development. Basic fibroblast growth factor (bFGF) induced morphological changes in CHP100 cells,...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.12.5.2193
更新日期:1992-05-01 00:00:00
abstract::IME1 encodes a transcriptional activator required for the transcription of meiosis-specific genes and initiation of meiosis in Saccharomyces cerevisiae. The transcription of IME1 is repressed in the presence of glucose, and a low basal level of IME1 RNA is observed in vegetative cultures with acetate as the sole carbo...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.18.4.1985
更新日期:1998-04-01 00:00:00
abstract::In in vitro splicing reactions, influenza virus NS1 mRNA was not detectably spliced, but nonetheless very efficiently formed ATP-dependent 55S complexes containing the U1, U2, U4, U5, and U6 small nuclear ribonucleoproteins (snRNPs) (C. H. Agris, M. E. Nemeroff, and R. M. Krug, Mol. Cell. Biol. 9:259-267, 1989). We de...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.12.3.962
更新日期:1992-03-01 00:00:00
abstract::The apoptotic process is accompanied by major changes in chromatin structure and gene expression. The apoptotic genetic program is progressively set up with the inhibition of antiapoptotic genes and the activation of proapoptotic ones. Here, we show that the histone deacetylase 3 (HDAC-3), which is a known co-represso...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.00869-06
更新日期:2007-01-01 00:00:00
abstract::FOXN1 is a prodifferentiation transcription factor in the skin epithelium. Recently, it has also emerged as an important player in controlling the skin wound healing process, as it actively participates in reepithelialization and is thought to be responsible for scar formation. FOXN1 positivity is also a feature of pi...
journal_title:Molecular and cellular biology
pub_type: 杂志文章,评审
doi:10.1128/MCB.00110-17
更新日期:2017-08-11 00:00:00
abstract::Nuclear pore complexes (NPCs) play an essential role in RNA export. Nucleoporins required for mRNA export in Saccharomyces cerevisiae are found in the Nup84p and Nup82p subcomplexes of the NPC. The Nup82p subcomplex contains Nup82p, Rat7p/Nup159p, Nsp1p, Gle1p/Rss1p, and Rip1p/Nup42p and is found only on the cytoplasm...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.24.11.4869-4879.2004
更新日期:2004-06-01 00:00:00