Research articles

Deletions on chromososme 5q are associated with myelodysplastic lesions. The genes responsible have largely remained elusive. But use of an RNA interference-based approach that can identify haploinsufficient tumour suppressor genes identifies RPS14, which regulates ribosomal RNA processing as a candidate tumour suppressor gene responsible for this so-called 5q⁻ syndrome.

Degradation of bacterial mRNAs involves internal cleavage events, but internal cleavage is prevented until the 5' triphosphate of the mRNA is converted to a monophosphate. However, the identity of this pyrophosphatase was unknown. This work shows that the product of the NudH gene (now called RppH) possesses this activity and accelerates mRNA degradation in vivo. This enzyme is a member of the Nudix family of pyrophosphohydrolases.

A large amount of water could potentially reside in the Earth's mantle transition zone, as two minerals there, wadsleyite and ringwoodite, can store significant amounts of water in their crystal structure. This paper reports the electrical conductivity measurements of these minerals, and finds that they can explain observed conductivity-depth profiles without introducing a significant amount of water into the mantle transition zone.

Clear Fano resonances that can be tuned by changing the device design or with applied voltages are observed. In the nonlinear regime, the visibility of the Fano interferences increases dramatically, which could be used as a sensitive probe of the degree of coupling between discrete states and the continuum, which is relevant for example for qubits where coupling to the environment needs to be kept to a minimum.

The balance of oxygen production over three years at sites in the North and South Pacific subtropical gyres is examined using oxygen sensors deployed on profiling floats. It is found that mixing events during early winter homogenize the upper water column and cause low oxygen concentrations. Oxygen then increases below the mixed layer at a nearly constant rate that is similar to independent measures of net community production.

A versatile system, based on modular DNA hairpins, that allows assembly and disassembly pathways to be programmed into DNA building blocks is described. A key development is the reaction graph, a simple representation of DNA modules and their interactions that simplifies the overall design process. In this way, it is possible to write assembly programs that are executed to prepare branched junction molecules, self-catalysing pairs of DNA duplexes and molecular trees.

A certain class of neurons in the swamp sparrow forebrain displays a precise auditory–vocal correspondence, and it is shown that these neurons respond in a temporally precise fashion to auditory presentation of certain note sequences in this songbird's repertoire and to similar note sequences in other birds' songs.

Telogen lag is a delay period where the hair follicle is refractive to signals that stimulate regeneration. Even though this concept has been around for over 50 years, the molecular mechanisms behind this phenomenon are still poorly understood. This paper shows that bone morphogenetic proteins (BMPs) and their inhibitors are crucial molecules in controlling hair follicle waves and cycling.

Listeria monocytogenes multiplies rapidly in the cytosol of infected cells, but has also been found in intracellular vacuoles during persistent infection. Now, these vacuoles are described as sites of comparably slow bacterial replication, which may promote bacterial survival in face of the host immune response.

The isolation of tumour-initiating cells from human melanomas is reported, with preliminary evidence suggesting that these melanoma stem cells can be specifically targeted with antibodies targeted against ABCB5, which offers a potential therapeutic strategy against melanomas.

Chronic pain is an unwelcome consequence of inflammatory disease and nerve injury that currently has no effective treatment. This paper shows that specific pharmacological inhibition of α2 and α3 subunits of GABA_A receptors is an effective therapy for inflammatory and neuropathic pain in rats.

The gene polar granule component (pgc) has been implicated in the global repression of transcription that occurs in Drosophila germline progenitors and was thought to act as a non-coding RNA. This paper shows that pgc encodes a small protein that represses transcription by preventing recruitment of the elongation factor P-TEFb.

The HIV protein Vpu is required for the release of viral particles. This paper shows that it counteracts the host cell protein CD317, renamed as tetherin. Tetherin is involved in the retention of newly budded HIV-1 virions at the cell surface.

Cytoplasmic RIG-like helicases are sensors of viral RNA, and signal through the mitochondrial adaptor protein MAVS to activate IRF3 and induce type 1 interferon production. This paper shows that a member of the NLR family of proteins called NLRX1 is a negative regulator of the pathway and functions by inhibiting the interaction of the viral sensor with the MAVS adaptor.

Calcium signalling is important for apicomplexan parasite virulence. A newly discovered calcium signalling pathway based on the plant hormone abscisic acid is now reported in Toxoplasma gondii. As this pathway is absent in most animals, it may present a new target for drug intervention.

Gamma-ray line radiation at 511 keV is the signature of electron–positron annihilation, which comes from the general direction of the Galactic centre, but the origin of the positrons was a mystery. This paper reports a distinct asymmetry in the 511 keV line emission coming from the inner Galactic disk, which resembles an asymmetry in the distribution of low mass X-ray binaries with strong emission at photon energies >20 keV, indicating that they may be the dominant origin of the positrons.

The availability of genomic data for many species is shedding light on the origin of sex and mating types over evolutionary time. This paper describes the sex-determination region of a zygomycete, the fungus Phycomyces blakesleeanus.