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Summary Replisome assembly at eukaryotic replication forks connects the DNA helicase to DNA polymerases and many other factors. The helicase binds the leading-strand polymerase directly, but is connected to the Pol α lagging-strand polymerase by the trimeric adaptor Ctf4. Here, we identify new Ctf4 partners in addition to Pol α and helicase, all of which contain a “Ctf4-interacting-peptide” or CIP-box. Crystallographic analysis classifies CIP-boxes into two related groups that target different sites on Ctf4. Mutations in the CIP-box motifs of the Dna2 nuclease or the rDNA-associated protein Tof2 do not perturb DNA synthesis genome-wide, but instead lead to a dramatic shortening of chromosome 12 that contains the large array of rDNA repeats. Our data reveal unexpected complexity of Ctf4 function, as a hub that connects multiple accessory factors to the replisome. Most strikingly, Ctf4-dependent recruitment of CIP-box proteins couples other processes to DNA synthesis, including rDNA copy-number regulation., Graphical Abstract, Highlights • Ctf4 is a hub that links factors with diverse functions to the eukaryotic replisome • Multiple Ctf4 partners bind via short sequences called “CIP-boxes” • The CIP-boxes of Dna2 and Tof2 bind to distinct sites on Ctf4 • Interaction of Dna2 and Tof2 with Ctf4 is important for rDNA copy number maintenance, Villa et al. identify Ctf4 as a key hub in the eukaryotic replisome. Rather than simply linking DNA helicase to DNA polymerase, Ctf4 couples the replication machinery to multiple factors that contribute to diverse aspects of chromosome duplication.

A dynamic multi-protein assembly known as the replisome is responsible for DNA synthesis in eukaryotic cells. In yeast, the hub protein Ctf4 bridges DNA helicase and DNA polymerase and recruits factors with roles in metabolic processes coupled to DNA replication. An important question in DNA replication is the extent to which the molecular architecture of the replisome is conserved between yeast and higher eukaryotes. Here, we describe the biochemical basis for the interaction of the human CTF4-orthologue AND-1 with DNA polymerase α (Pol α)/primase, the replicative polymerase that initiates DNA synthesis. AND-1 has maintained the trimeric structure of yeast Ctf4, driven by its conserved SepB domain. However, the primary interaction of AND-1 with Pol α/primase is mediated by its C-terminal HMG box, unique to mammalian AND-1, which binds the B subunit, at the same site targeted by the SV40 T-antigen for viral replication. In addition, we report a novel DNA-binding activity in AND-1, which might promote the correct positioning of Pol α/primase on the lagging-strand template at the replication fork. Our findings provide a biochemical basis for the specific interaction between two critical components of the human replisome, and indicate that important principles of replisome architecture have changed significantly in evolution.

Hepatic blood flow and peripheral plasma renin activity were determined in 15 true renovascular hypertensive patients and in 13 patients with essential hypertension. In the renovascular hypertensives, plasma renin activity and hepatic blood flow were negatively correlated ( p less than 0.01). In contrast, no relationship was observed in the essential hypertensives. The study suggests that hyperactivity of the renin-angiotensin system could induce splanchnic arteriolar constriction in patients with renovascular hypertension.

Les effets hemodynamiques de la nicergoline sont etudies chez 12 hypertendus permanents essentiels. La nicergoline est administree en perfusion continue a la dose de 0,20 a 0,50 mg/min. Il existe un abaissement significatif et rapide des pressions arterielles systolique et diastolique, des resistances peripheriques (P

Geochimica et Cosmochimica Acta, 69 (10 / Supplement), ISSN:0016-7037, ISSN:1872-9533

A dynamic multi-protein assembly known as the replisome is responsible for DNA synthesis in eukaryotic cells. In yeast, the hub protein Ctf4 bridges DNA helicase and DNA polymerase and recruits factors with roles in metabolic processes coupled to DNA replication. An important question in DNA replication is the extent to which the molecular architecture of the replisome is conserved between yeast and higher eukaryotes. Here we describe the biochemical basis for the interaction of the human CTF4-orthologue AND-1 with Pol α/primase, the replicative polymerase that initiates DNA synthesis. AND-1 has maintained the trimeric structure of yeast Ctf4, driven by its conserved SepB domain. However, the primary interaction of AND-1 with Pol α/primase is mediated by its C-terminal HMG box, unique to mammalian AND-1, which binds the B subunit, at the same site targeted by the SV40 T antigen for viral replication. In addition, we report a novel DNA-binding activity in AND-1, which might promote the correct positioning of Pol α/primase on the lagging-strand template at the replication fork. Our findings provide a biochemical basis for the specific interaction between two critical components of the human replisome, and indicate that important principles of replisome architecture have changed significantly in evolution.

Echocardiographic determinations, left ventricular mass-volume ratio ( M V ), left ventricular end-systolic stress (ESS), carotidofemoral pulse wave velocity (PWV), and brachial artery compliance (BAC), deduced from pulsed Doppler measurements and from the Bramwell-Hill equation, were evaluated in 20 patients with sustained essential hypertension in comparison with 20 control subjects of the same age and sex. In hypertensive patients, M V ratio, ESS, and PWV were significantly increased while BAC was reduced. In the overall population, ESS was directly correlated with PWV (r = 0.73), and M V ratio was significantly correlated with PWV (r = 0.60), BAC (r = −0.70), and systolic arterial pressure (r = 0.71). No comparable results were observed with diastolic arterial pressure. PWV was unchanged after cadralazine, a dihydralazine-like substance, and was decreased with the same blood pressure reduction following nitrendipine, a new calcium-blocking agent. These results suggest that: (1) the distensibility of large arteries plays an important role in the maintenance of cardiac hypertrophy in hypertension, and (2) antihypertensive drugs may act differently on arterial distensibility with possible consequences on ESS and reversion of left ventricular hypertrophy.