The 3′→5′ exonuclease of DNA polymerase δ can substitute for the 5′ flap endonuclease Rad27/Fen1 in processing Okazaki fragments and preventing genome instability

Many DNA polymerases (Pol) have an intrinsic 3′→5′ exonuclease (Exo) activity which corrects polymerase errors and prevents mutations. We describe a role of the 3′→5′ Exo of Pol δ as a supplement or backup for the Rad27/Fen1 5′ flap endonuclease. A yeast rad27 null allele was lethal in combination with Pol δ mutations in Exo I, Exo II, and Exo III motifs that inactivate its exonuclease, but it was viable with mutations in other parts of Pol δ. The rad27-p allele, which has little phenotypic effect by itself, was also lethal in combination with mutations in the Pol δ Exo I and Exo II motifs. However, rad27-p Pol δ Exo III double mutants were viable. They exhibited strong synergistic increases in CAN1 duplication mutations, intrachromosomal and interchromosomal recombination, and required the wild-type double-strand break repair genes RAD50, RAD51, and RAD52 for viability. Observed effects were similar to those of the rad27-null mutant deficient in the removal of 5′ flaps in the lagging strand. These results suggest that the 3′→5′ Exo activity of Pol δ is redundant with Rad27/Fen1 for creating ligatable nicks between adjacent Okazaki fragments, possibly by reducing the amount of strand-displacement in the lagging strand.

Inhibition of Auxin Movement from the Shoot into the Root Inhibits Lateral Root Development in Arabidopsis1

In roots two distinct polar movements of auxin have been reported that may control different developmental and growth events. To test the hypothesis that auxin derived from the shoot and transported toward the root controls lateral root development, the two polarities of auxin transport were uncoupled in Arabidopsis. Local application of the auxin-transport inhibitor naphthylphthalamic acid (NPA) at the root-shoot junction decreased the number and density of lateral roots and reduced the free indoleacetic acid (IAA) levels in the root and [3H]IAA transport into the root. Application of NPA to the basal half of or at several positions along the root only reduced lateral root density in regions that were in contact with NPA or in regions apical to the site of application. Lateral root development was restored by application of IAA apical to NPA application. Lateral root development in Arabidopsis roots was also inhibited by excision of the shoot or dark growth and this inhibition was reversible by IAA. Together, these results are consistent with auxin transport from the shoot into the root controlling lateral root development.

A behavioral screen for isolating zebrafish mutants with visual system defects.

Optokinetic and phototactic behaviors of zebrafish larvae were examined for their usefulness in screening for recessive defects in the visual system. The optokinetic response can be reliably and rapidly detected in 5-day larvae, whereas the phototactic response of larvae is variable and not robust enough to be useful for screening. We therefore measured optokinetic responses of mutagenized larvae as a genetic screen for visual system defects. Third-generation larvae, representing 266 mutagenized genomes, were examined for abnormal optokinetic responses. Eighteen optokinetic-defective mutants were identified and two mutants that did not show obvious morphological defects, no optokinetic response a (noa) and partial optokinetic response a (poa), were studied further. We recorded the electroretinogram (ERG) to determine whether these two mutations affect the retina. The b-wave of noa larvae was grossly abnormal, being delayed in onset and significantly reduced in amplitude. In contrast, the ERG waveform of poa larvae was normal, although the b-wave was reduced in amplitude in bright light. Histologically, the retinas of noa and poa larvae appeared normal. We conclude that noa larvae have a functional defect in the outer retina, whereas the outer retina of poa larvae is likely to be normal.

Map of Lodi Township. Town three south. Range five east [plat]

Publication information: Chicago, Ill. : Everts & Stewart, 1874.

Map of Bridgewater Township. Town four south. Range four east [plat]

Compiled & Drawn by P. H. Dowling. Publication information: Chicago, Ill. : Everts & Stewart, 1874.

Map of York Township. Town four south. Range six east [plat]

Publication information: Chicago, Ill. : Everts & Stewart, 1874.

Map of Augusta Township. Town four south. Range seven east [plat]

Publication information: Chicago, Ill. : Everts & Stewart, 1874.

UM Women's Volleyball Team, 1992

Front Row: Erica Badran-Grycan, Fiona Davidson, Kathy Richards, Chris White, Hayley Lorenzen, Tarnisha Thompson, Michelle Horrigan, LaShawnda Crowe,

Back Row: assistant coach Mora Kanim, Kathy Jacobsen, Julie Scherer, Robyn Read, head coach Greg Giovanazzi, JoAnna Collias, Suzy O' Donnell, Aimee Smith, Marita McCahill, assistant coach Jennifer Dhaenens.

Predicting the demand for high occupancy vehicle lanes. Final report.

Federal Highway Administration, Office of Traffic Management and IVHS, Washington, D.C.

Caregivers of the frail elderly : a national profile /

Item 491-B-17

Kaleidophone : new resources of melody and harmony : pitch scales in relation to chord structures : an aid to composers, performers, arrangers, teachers, song-writers, students, conductors, critics, and all who work with music /

Mode of access: Internet.

Evaluation of New York State's Mandatory Occupant Restraint Law: volume V - fatalities and injuries among motor vehicle occupants covered by the law.

National Highway Traffic Safety Administration, Washington, D.C.

Healthy living,

Book 1 contains a chapter on "Physical exercises," book 2 a chapter on "Sport and health," by Walter Camp. Supplements in book one and two, by Oscar Dowling.