100 research outputs found

    A role for Tctex-1 (DYNLT1) in controlling primary cilium length

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    The microtubule motor complex cytoplasmic dynein is known to be involved in multiple processes including endomembrane organization and trafficking, mitosis, and microtubule organization. The majority of studies of cytoplasmic dynein have focussed on the form of the motor that is built around the dynein-1 heavy chain. A second isoform, dynein heavy chain-2, and its specifically associated light intermediate chain, LIC3 (D2LIC), are known to be involved in the formation and function of primary cilia. We have used RNAi in human epithelial cells to define the cytoplasmic dynein subunits that function with dynein heavy chain 2 in primary cilia. We identify the dynein light chain Tctex-1 as a key modulator of cilia length control; depletion of Tctex-1 results in longer cilia as defined by both acetylated tubulin labelling of the axoneme and Rab8a labelling of the cilia membrane. Suppression of dynein heavy chain-2 causes concomitant loss of Tctex-1 and this correlates with an increase in cilia length. Compared to individual depletions, double siRNA depletion of DHC2 and Tctex-1 causes an even greater increase in cilia length. Our data show that Tctex-1 is a key regulator of cilia length and most likely functions as part of dynein-2

    The Munster Plantation, 1583-1641

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    The subject concerns the settlement of English families in southern Ireland after the death in rebellion of the last earl of Desmond. The survey commission of 1584 reveals the fragmented extent of escheated land and the haphazard nature of confiscation. The decision to colonise from England was not taken until consideration had been made of several alternative schemes. It is shown that the questions of moral legitimacy for the plantation and the general thrust of government policy - much worried over by historians today - did not preoccupy those planning the Munster venture. Brief mention is made over the background of the settlers and their recruitment and grouping. It is shown that a proportion of leading colonists were army men or administrators on the Irish establishment, many of whom with insufficient wealth or influence in England to promote their stipulated settlement. Because of faulty direction and the practical difficulties of such a vast project, assigning land and settling the newcomers took several years. Land claims from local inhabitants further slowed events. The English settlers in the 1590s numbered 3,500 and invested about 20,000 in the plantation. This sum and the small population proved inadequate faced with the rising in 1598. Re-establishment of the plantation in the 17th century was at a much higher level, the English population becoming four times greater in the 1620s than the 1590s, and powerful enough to control a considerable area after the 1641 rebellion. Motives for this increased emigration to Munster are then examined. The traditional reasons - land, new jobs, religious freedom, social advancement, escape from authority - are paraded and found wanting. The final, geographical explanation comes in the last chapter which also establishes the extent to which the English modified Munster and in turn were changed by local conditions. In an appendix are included brief biographical entries of the 35 chief settlers and the fate of their portions up to 1641. <p

    The hallmarks of cancer are also the hallmarks of wound healing

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    A novel large deletion and single nucleotide insertion in the Wiskott-Aldrich syndrome protein gene

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    Deletion mutations of WAS are relatively rare and the precise localization of large deletions in the genome has rarely been described in previous studies. We report here a five-months-old boy with a large deletion mutation in WAS that completely abolished protein expression. In order to localize the deletion, a 2816 bp-length sequence that spans between exons 9 and 12 was amplified. PCR amplification of the patient's sample revealed a single band of about 1 kb in contrast to the 2816 bp amplicon in the control. Genomic DNA sequencing of the patient revealed a 1595 bp deletion and an adenine insertion (g.5247_6841del1595insA). This large deletion of WAS resulted in partial loss of exon 10 and intron 11, and a complete loss of intron 10 and exon 11. This article is protected by copyright. All rights reserved

    A role for the Golgi matrix protein giantin in ciliogenesis through control of the localization of dynein-2

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    The correct formation of primary cilia is central to the development and function of nearly all cells and tissues. Cilia grow from the mother centriole by extension of a microtubule core, the axoneme, which is then surrounded with a specialized ciliary membrane that is continuous with the plasma membrane. Intraflagellar transport moves particles along the length of the axoneme to direct assembly of the cilium and is also required for proper cilia function. The microtubule motor, cytoplasmic dynein-2 mediates retrograde transport along the axoneme from the tip to the base; dynein-2 is also required for some aspects of cilia formation. In most cells, the Golgi lies adjacent to the centrioles and key components of the cilia machinery localize to this organelle. Golgi-localized proteins have also been implicated in ciliogenesis and in intraflagellar transport. Here, we show that the transmembrane Golgi matrix protein giantin (GOLGB1) is required for ciliogenesis. We show that giantin is not required for the Rab11–Rabin8–Rab8 pathway that has been implicated in the early stages of ciliary membrane formation. Instead we find that suppression of giantin results in mis-localization of WDR34, the intermediate chain of dynein-2. Highly effective depletion of giantin or WDR34 leads to an inability of cells to form primary cilia. Partial depletion of giantin or of WDR34 leads to an increase in cilia length consistent with the concept that giantin acts through dynein-2. Our data implicate giantin in ciliogenesis through control of dynein-2 localization

    Politics, 1641-1660

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    The therapeutic potential of a series of orally bioavailable anti-angiogenic microtubule disruptors as therapy for hormone-independent prostate and breast cancers

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    Therapies for hormone-independent prostate and breast cancer are limited, with the effectiveness of the taxanes compromised by toxicity, lack of oral bioavailability and drug resistance. This study aims to identify and characterise new microtubule disruptors, which may have improved efficacy relative to the taxanes in hormone-independent cancer. 2-Methoxy-3-O-sulphamoyl-17β-cyanomethyl-oestra-1,3,5(10)-triene (STX641), 2-methoxy-3-hydroxy-17β-cyanomethyl-oestra-1,3,5(10)-triene (STX640) and 2-methoxyoestradiol-3,17-O,O-bis-sulphamate (STX140) were all potent inhibitors of cell proliferation in a panel of prostate and breast cancer cell lines. STX641 and STX640 significantly inhibited tumour growth in the MDA-MB-231 xenograft model. STX641 inhibited both in vitro and in vivo angiogenesis. Despite good in vivo activity, STX641 was not as potent in vivo as STX140. Therefore, STX140 was evaluated in the prostate hormone-independent PC-3 xenograft model. STX140 had superior efficacy to docetaxel, 2-MeOE2 and bevacizumab. In contrast to vinorelbine, no significant toxicity was observed. Furthermore, STX140 could be dosed daily over a 60-day period leading to tumour regression and complete responses, which were maintained after the cessation of dosing. This study demonstrates that STX641 and STX140 have considerable potential for the treatment of hormone-independent breast and prostate cancer. In contrast to the taxanes, STX140 can be dosed orally, with no toxicity being observed even after prolonged daily dosing
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