Daughter cells share duties

Dying on cue

sea-maid submitted, created time 6 months 1 week (www.jcb.org)

Earnshaw's group was hoping to crack a different question: how the cell's chromatin condenses during mitosis. In order to find the answer, they allowed researchers to create synchronized systems to study how protein-slicing enzymes such as the caspases orchestrate apoptosis.

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Cutting the cord--mitosis and separation

sea-maid submitted, created time 6 months 1 week (www.jcb.org)

From this resport, we know that like parents sending their child off to college, a dividing cell has to let its offspring go. A microtubule-organizing protein helps ensure that the daughter cell breaks free.

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MYPT1 regulates mitosis by antagonizing Plk1

Cdc20 and Cks Direct the Spindle Checkpoint-Independent Destruction of Cyclin A

Rac1 takes a trip

sea-maid submitted, created time 6 months 4 weeks (www.jcb.org)

This article shows us about enzyme Rac1, which is active whenever a cell is on the move or tangling with invading bacteria. It shuttles into and out of the nucleus to help induce mitosis. But the reason Rac1 enters the nucleus is also mysterious.

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cytokinesis unveiled: forming the furrows

Structure, dynamics, and evolution of centromeric nucleosomes

jimmy submitted, created time 1 year 2 months (www.pnas.org)

Centromeres are defining features of eukaryotic chromosomes, providing sites of attachment for segregation during mitosis and meiosis. The fundamental unit of centromere structure is the centromeric nucleosome, which differs from the conventional nucleosome by the presence of a centromere-specific histone variant (CenH3) in place of canonical H3.

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Chromatin fine structure of the c-MYC insulator element/DNase I-hypersensitive site I is not preserved during mitosis

davis submitted, created time 1 year 2 months (www.pnas.org)

During mitosis in higher eukaryotic cells, transcription is silenced and transcription complexes are absent from promoters in the condensed chromosomes; however, epigenetic information concerning the pattern of expressed and silent genes must be preserved.

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Tension and Microtubule dynamics

big pig submitted, created time 1 year 5 months (www.nature.com)

During mitosis, kinetochores attach chromosomes to the tips of growing and shortening microtubules. Asbury and colleagues demonstrate that the level of tension applied through optical tweezers to the budding yeast kinetochore component Dam1 attached to a microtubule tip determines parameters of microtubule dynamics and ultimately, the length of the mitotic microtubules.

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The Spindle Pole Bodies Facilitate Nuclear Envelope Division during Closed Mitosis in Fission Yeast

diggman submitted, created time 1 year 5 months (biology.plosjournals.org)

Here, we show that fission yeast cells overexpressing the transforming acid coiled coil (TACC)-related protein, Mia1p/Alp7p, failed to separate the spindle pole bodies (SPBs) at the onset of mitosis, but could assemble acentrosomal bipolar and antiparallel spindle structures.

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Emi1 is needed to couple DNA replication with mitosis but does not regulate activation of the mitotic APC/C

athena submitted, created time 1 year 6 months (www.jcb.org)

"Ubiquitin-mediated proteolysis is critical for the alternation between DNA replication and mitosis and for the key regulatory events in mitosis. The anaphase-promoting complex/cyclosome (APC/C) is a conserved ubiquitin ligase that has a fundamental role in regulating mitosis and the cell cycle in all eukaryotes. In vertebrate cells, early mitotic inhibitor 1 (Emi1) has been proposed as an important APC/C inhibitor whose destruction may trigger activation of the APC/C at mitosis. "

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Inactivation of the ubiquitin conjugating enzyme UBE2Q2 causes a prophase arrest and enhanced apoptosis in response to microtubule inhibiting agents

cappuccion submitted, created time 1 year 6 months (www.nature.com)

A putative ubiquitin conjugating enzyme known as UBE2Q2 was previously identified in a microarray screen for mitotic regulatory proteins. UBE2Q2 is very similar to another human protein, UBE2Q1 and orthologs from other higher eukaryotic species. In these studies, we demonstrate that UBE2Q2 can covalently bind ubiquitin on the active site cysteine in vitro and show that inhibition of this protein in vivo causes an early mitotic arrest and increased cytotoxicity when cells are treated with microtubule inhibiting agents (MIAs).

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