Microtubule-associated Proteins 1 (MAP1) Promote Human Immunodeficiency Virus Type I (HIV-1) Intracytoplasmic Routing to the Nucleus

After cell entry, HIV undergoes rapid transport toward the nucleus using microtubules and microfilaments. Neither the cellular cytoplasmic components nor the viral proteins that interact to mediate transport have yet been identified. Using a yeast two-hybrid screen, we identified four cytoskeletal components as putative interaction partners for HIV-1 p24 capsid protein: MAP1A, MAP1S, CKAP1, and WIRE. Depletion of MAP1A/MAP1S in indicator cell lines and primary human macrophages led to a profound reduction in HIV-1 infectivity as a result of impaired retrograde trafficking, demonstrated by a characteristic accumulation of capsids away from the nuclear membrane, and an overall defect in nuclear import. MAP1A/MAP1S did not impact microtubule network integrity or cell morphology but contributed to microtubule stabilization, which was shown previously to facilitate infection. In addition, we found that MAP1 proteins interact with HIV-1 cores both in vitro and in infected cells and that interaction involves MAP1 light chain LC2. Depletion of MAP1 proteins reduced the association of HIV-1 capsids with both dynamic and stable microtubules, suggesting that MAP1 proteins help tether incoming viral capsids to the microtubular network, thus promoting cytoplasmic trafficking. This work shows for the first time that following entry into target cells, HIV-1 interacts with the cytoskeleton via its p24 capsid protein. Moreover, our results support a role for MAP1 proteins in promoting efficient retrograde trafficking of HIV-1 by stimulating the formation of stable microtubules and mediating the association of HIV-1 cores with microtubules.     

Ethical tissue: a not-for-profit model for human tissue supply

Following legislative changes in 2004 and the establishment of the Human Tissue Authority, access to human tissues for biomedical research became a more onerous and tightly regulated process. Ethical Tissue was established to meet the growing demand for human tissues, using a process that provided ease of access by researchers whilst maintaining the highest ethical and regulatory standards. The establishment of a licensed research tissue bank entailed several key criteria covering ethical, legal, financial and logistical issues being met. A wide range of stakeholders, including the HTA, University of Bradford, flagged LREC, hospital trusts and clinical groups were also integral to the process.     

Isolation of high molecular weight DNA suitable for BAC library construction from woody perennial soft-fruit species

We have developed a novel nuclei extraction method that allows for the extraction of high molecular weight DNA from leaves of woody perennial soft-fruit species that contain high levels of carbohydrates and polyphenolics. The method utilizes a modified buffer system including 4% (w/v) polyvinylpyrrolidone (PVP)-10 and a combination of nylon filters and Percoll gradients to purify nuclei extracts prior to embedding in agarose plugs. The effectiveness of the method was demonstrated on leaves of red raspberry (Rubus idaeus) and blackcurrant (Ribes nigrum), two soft-fruit species that have shown to be recalcitrant to standard genomic DNA extraction methods. Extracted DNA was readily digested by restriction enzymes and, as shown for raspberry, suitable for bacterial artificial chromosome (BAC) library construction.     

The origin of the pelagobenthic metazoan life cycle: what's sex got to do with it?

The biphasic (pelagobenthic) life cycle is found throughoutthe animal kingdom, and includes gametogenesis, embryogenesis,and metamorphosis. From a tangled web of hypotheses on the originand evolution of the metazoan pelagobenthic life cycle, currentopinion appears to favor a simple, larval-like holopelagic ancestorthat independently settled multiple times to incorporate a benthicphase into the life cycle. This hypothesis derives originallyfrom Haeckel's (1874) Gastraea theory of ontogeny recapitulatingphylogeny, in which the gastrula is viewed as the recapitulationof a gastraean ancestor that evolved via selection on a simple,planktonic hollow ball of cells to develop the capacity to feed.Here, we propose an equally plausible hypothesis that the originof the metazoan pelagobenthic life cycle was a direct consequenceof sexual reproduction in a likely holobenthic ancestor. Indoing so, we take into account new insights from poriferan developmentand from molecular phylogenies. In this scenario, the gastruladoes not represent a recapitulation, but simply an embryologicalstage that is an outcome of sexual reproduction. The embryocan itself be considered as the precursor to a biphasic lifestyle,with the embryo representing one phase and the adult anotherphase. This hypothesis is more parsimonious because it precludesthe need for multiple, independent origins of the benthic form.It is then reasonable to consider that multilayered, ciliatedembryos ultimately released into the water column are subjectto natural selection for dispersal/longevity/feeding that setsthem on the evolutionary trajectory towards the crown metazoanplanktonic larvae. These new insights from poriferan developmentthus clearly support the intercalation hypothesis of bilaterianlarval evolution, which we now believe should be extended todiscussions of the origin of biphasy in the metazoan last commonancestor.     

Writing In and Reading ICU Diaries: Qualitative Study of Families' Experience in the ICU

Purpose

Keeping an ICU patient diary has been reported to benefit the patient''s recovery. Here, we investigated the families'' experience with reading and writing in patient ICU diaries kept by both the family and the staff.

Methods

We conducted a qualitative study involving 32 semi-structured in-depth interviews of relatives of 26 patients (34% of all family members who visited patients) who met our ICU-diary criterion, i.e., ventilation for longer than 48 hours. Grounded theory was used to conceptualise the interview data via a three-step coding process (open coding, axial coding, and selective coding).

Results

Communicative, emotional, and humanising experiences emerged from our data. First, family members used the diaries to access, understand, and assimilate the medical information written in the diaries by staff members, and then to share this information with other family members. Second, the diaries enabled family members to maintain a connection with the patient by documenting their presence and expressing their love and affection. Additionally, families confided in the diaries to maintain hope. Finally, family members felt the diaries humanized the medical staff and patient.

Conclusions

Our findings indicate positive effects of diaries on family members. The diaries served as a powerful tool to deliver holistic patient- and family-centered care despite the potentially dehumanising ICU environment. The diaries made the family members aware of their valuable role in caring for the patient and enhanced their access to and comprehension of medical information. Diaries may play a major role in improving the well-being of ICU-patient families.     

Mutagenesis screens for interacting genes reveal three roles for fat facets during Drosophila eye development

The Drosophila fat facets gene encodes a deubiquitinating enzyme that regulates a cell communication pathway essential early during eye development to inhibit the determination of excess photoreceptors. Ubiquitin is a small polypeptide that tags proteins for degradation by a multisubunit proteolytic complex called the proteasome. The FAT FACETS protein is thought to be required to remove ubiquitin from a particular protein, thereby rescuing it from proteolysis. In order to identify the genes encoding the substrate of FAT FACETS and other components of the neural inhibition pathway, a mutagenesis screen for dominant enhancers of the fat facets mutant eye phenotype was performed. Several genes were identified, one of which is an excellent candidate for encoding a component of the pathway regulated by FAT FACETS. Three different eye phenotypes were observed when the fat facets mutants were dominantly enhanced by different mutations, suggesting that fat facets has other functions in addition to its critical role early in eye development. Dev. Genet. 21:167–174, 1997. © 1997 Wiley-Liss, Inc.     

Induction of metamorphosis with potassium ions requires development of competence and an anterior signalling centre in the ascidian Herdmania momus

 Increased K⁺ concentration in seawater induces metamorphosis in the ascidian Herdmania momus. Larvae cultivated at 24°C exhibit highest rates of metamorphosis when treated with 40 mM KCl-elevated seawater at 21°C. At 24°C, H. momus larvae develop competence to respond to KCl-seawater and initiate metamorphosis approximately 3 h after hatching. Larval trunks and tails separated from the anterior papillae region, but maintained in a common tunic at a distance of greater than 60 μm, do not undergo metamorphosis when treated with KCl-seawater; normal muscle degradation does not occur in separated tails while ampullae develop from papillae-containing anterior fragments. Normal programmed degradation of myofibrils occurs when posterior fragments are fused to papillae-containing anterior fragments. These data indicate that H. momus settlement and metamorphosis only occurs when larvae have attained competence, and suggest that an anterior signalling centre is stimulated to release a factor that induces metamorphosis. Received: 15 May 1996 / Accepted: 19 September 1996     

Replication-competent influenza A virus that encodes a split-green fluorescent protein-tagged PB2 polymerase subunit allows live-cell imaging of the virus life cycle

Studies on the intracellular trafficking of influenza virus ribonucleoproteins are currently limited by the lack of a method enabling their visualization during infection in single cells. This is largely due to the difficulty of encoding fluorescent fusion proteins within the viral genome. To circumvent this limitation, we used the split-green fluorescent protein (split-GFP) system (S. Cabantous, T. C. Terwilliger, and G. S. Waldo, Nat. Biotechnol. 23:102-107, 2005) to produce a quasi-wild-type recombinant A/WSN/33/influenza virus which allows expression of individually fluorescent PB2 polymerase subunits in infected cells. The viral PB2 proteins were fused to the 16 C-terminal amino acids of the GFP, whereas the large transcomplementing GFP fragment was supplied by transient or stable expression in cultured cells that were permissive to infection. This system was used to characterize the intranuclear dynamics of PB2 by fluorescence correlation spectroscopy and to visualize the trafficking of viral ribonucleoproteins (vRNPs) by dynamic light microscopy in live infected cells. Following nuclear export, vRNPs showed a transient pericentriolar accumulation and intermittent rapid (～1 μm/s), directional movements in the cytoplasm, dependent on both microtubules and actin filaments. Our data establish the potential of split-GFP-based recombinant viruses for the tracking of viral proteins during a quasi-wild-type infection. This new virus, or adaptations of it, will be of use in elucidating many aspects of influenza virus host cell interactions as well as in screening for new antiviral compounds. Furthermore, the existence of cell lines stably expressing the complementing GFP fragment will facilitate applications to many other viral and nonviral systems.