Intron involvement in the regulation of MuSVts110 RNA splicing

The murine sarcoma virus MuSVts110 exhibits an alternative RNA splicing pattern. Like other simple retroviruses, MuSVts110 pre-mRNA splicing is balanced to allow the production of both spliced and unspliced RNA during the replicative cycle. In addition to balance, MuSVts110 RNA splicing exhibits a unique growth-temperature restriction to splicing; temperatures below 33$\sp\circ$C are permissive for splicing while temperatures of 37$\sp\circ$C or above are non-permissive. Previous work has established that this thermosensitive splicing phenotype is mediated in cis by viral transcript features. Here we show that at least three sequence elements regulate the MuSVts110 splicing phenotype. First, the MuSVts110 branchpoint (BP) and poly-pyrimidine tract (PPT) were found to be determinants of overall splicing efficiency. Wild-type MuSVts110 possesses a weak BP and PPT adjacent to the 3$\sp\prime$ splice site. Introduction of a strong BP caused MuSVts110 splicing to proceed to virtual completion in vivo, thus losing any vestige of balance or thermosensitivity. In in vitro splicing extracts, the strong BP overcame a blockade to wt MuSVts110 splicing at both the first and second catalytic steps. Weakening the consensus nature of the strong BP allowed the recovery of thermosensitive splicing in vivo, and reinstated the blockades to splicing in vitro, arguing that a suboptimal BP is an unusual manifestation of the proportional splicing pattern of retroviruses. The PPT is essential for accurate recognition of the BP sequence by the splicing machinery. Lengthening the PPT of MuSVts110 from 9 to 19 consecutive pyrimidines increased the overall efficiency of splicing in vivo dramatically, but was less effective than the strong BP in overriding the restriction on splicing imposed by high growth temperatures. Finally, decreasing gradually the overall size of the intron unexpectedly reduced splicing efficiency at growth temperatures permissive for splicing, suggesting that non-conserved sequences within the intron of MuSVts110 participate in splicing regulation as well. Taken together, these results suggest a mechanism of control in which MuSVts110 splicing is modulated by the entire intron, but principally by suboptimal signals at the splice acceptor site. Furthermore, this retroviral system provides a powerful genetic method for selection and analysis of mutations that affect splicing. ^

The regulation of JAB1 and its role in herceptin resistance

The Jun activation domain-binding protein (JAB1) is a c-Jun co-activator and a member of the COP9 signalosome. Additionally, it has recently been named a key negative regulator of the cyclin-dependent kinase inhibitor, p27. JAB1 overexpression has been observed in breast cancer and correlates with low p27 levels as well as poor prognosis, yet the mechanism of JAB1 deregulation is unknown. Data from our laboratory suggest that constitutive transcriptional activation of the jab1 gene is responsible for JAB1 protein overexpression. Therefore, we hypothesized that overexpression of JAB1 in breast cancer can be attributed to increased transcriptional activity. To identify potential positive regulators of JAB1, we characterized the promoter and found a 128 bp region that was critical for jab1 transcriptional activation. Our studies show that two oncogenic transcription factors, C/EBPβ and STAT3, play an important role in modulating jab1 transcription. Further, we have identified jab1 as a direct target gene of the SRC/STAT3 pathway. These studies provide insight to the mechanism of JAB1 overexpression in breast cancer and open up possibilities for therapies to inhibit its expression. ^ The development of the humanized monoclonal antibody, Herceptin (trastuzumab) targeting the HER2 (ErbB2) receptor has provided promising treatment to patients with aggressive HER2 positive breast cancer. However, many patients are resistant to Herceptin and additional therapies are needed to overcome resistance. Recent findings indicate that one mechanism of resistance involves AKT phosphorylation and subsequent mislocalization of the cyclin dependent kinase inhibitor, p27. We examined whether JAB1 facilitated degradation of p27 may be another mechanism of resistance to Herceptin. Our studies show that overexpression of JAB1 inhibited Herceptin induced G1-arrest and p27 accumulation. Interestingly, increased JAB1 levels were observed in two BT-474 Herceptin resistant clones. Targeted silencing of JAB1 increased p27 protein levels, reinstated a G1 checkpoint, and reduced cellular proliferation in the resistant clones. Our studies have demonstrated that inhibition of JAB1 sensitizes Herceptin resistant cells to treatment. Therefore, inhibition of JAB1 could provide a novel method of sensitizing resistant tumors to Herceptin-induced tumor growth arrest. ^

The campaign to save Croxteth comprehensive: an ethnographic study of a protest movement

This thesis is based on ethnographic research carried out on a Liverpool protest movement which occurred between November, 1980 and July,1983. The protest movement was waged by residents of the working class community of Croxteth Liverpool who wished to retain their state secondary school, Croxteth Comprehensive. The Liverpool City Council voted in favour of closing Croxteth Comprehensive in January, 1981 because of its declining roles. Residents began theIr campaign as soon as they became aware of intentions to close the school at the end of the previous year. The campaIgn itself went through a number of different phases, distinguishable accordIng to the groups of people involved, the strategy and tactics they employed, the ways in which they justified their campaign, and the goals they pursued. In July of 1982 the organisation which led the protest, the Croxteth Community Action Committee, took illegal possession of the school buildings and ran a pilot summer school project. In September of 1982 they opened the school doors for all secondary pupils on the council estate and began running classes, with the help of volunteer teachers. The school was run successfully in this way for the entire 1982/83 school year. By the end of this period the school was officially reinstated by a new Labour Party majorIty on the city council. This thesis presents a comprehensive account of the entire campaign, from its beginning to end. The campaign is analysed in a number of ways: by situating the closure itself in the economic and political conditions of Liverpool in the 1980s, by examining the relation of Croxteth Comprehensive to its community, by describing the conditions in which different groups of people contributed to the campaign and the changes it went through in its use of tactics, and through a close examination of the activities which took place inside the school during its year of occupation. A number of levels of analysis are used in the study. To explain the closure and the early forms of resistance which developed to oppose it, the structural location of the local government of Liverpool in the late 1970s and early 1980s is described. To explain the relationship of the school to its community, the formation of a group of activists and their leaders, and the resources available to the protestors for pursuing their aims, a single-group model of social action is used. To analyse the establishment of social routines and schooling practices within the school during its occupation, action-theoretica1 models are drawn upon., The chapters of literature review and concept analysis with which this thesis begins link these different levels theoretIcalIy through a model of actIon and its conditions. The theoretical framework employed is reviewed in the last chapter. It is one which could be used to study any social movement, and has applications to other social phenomena as well. Lastly various issues within the sociology of education are examined in light of the events which took place in Croxteth Comprehensive, especially the theory of community education.

Distribution of diatom species as abundance estimates from vertical multinet hauls from 150 m water depth in the Indian Ocean

During the Indian Ocean Expedition of R/V METEOR phytoplankton samples were taken with a multiple closing net (Multinet) at 103 stations. In this material the diatoms were investigated. In all 247 taxa could be identified which belong to 242 species and 5 varieties of formae of 80 genera. Of these 1 variety, 15 pecies, and 3 genera are newly described. New combinations were made for 18 species, and a number of old combinations was reinstated.

The glass coffin, to be or no to be Snow White

We can widen the notion of « end of life » by including lives that are out of the race/circuit, excluded from “active life” and economic usefulness, and which entered this other major area of life we usually consider as the garbage of existence. We could compare this space to the glass coffin where the dwarves secluded Snow White, neither alive nor dead, but in end of life. This “end of life” starts very early in institutions or for those who live in the streets. Our society reinstated, without noticing, a caste of “untouchables” with whom we don’t know anymore how to relate. Accompaniment of the end of life actually appears closely bound to accompaniment of these lives finished, considered as “obsoletes”, expendable, disturbing… It gradually appeared to me that my workshops with homeless people or people deeply damaged by addictions were closer to palliative care than to “psychotherapy”.