Intrinsic and environmental drivers of pairwise cohesion in wild Canis social groups.

Animals within social groups respond to costs and benefits of sociality by adjusting the proportion of time they spend in close proximity to other individuals in the group (cohesion). Variation in cohesion between individuals, in turn, shapes important group-level processes such as subgroup formation and fission-fusion dynamics. Although critical to animal sociality, a comprehensive understanding of the factors influencing cohesion remains a gap in our knowledge of cooperative behavior in animals.

Large carnivores avoid humans while prioritizing prey acquisition in anthropogenic areas.

Large carnivores are recovering in many landscapes where the human footprint is simultaneously growing. When carnivores encounter humans, the way they behave often changes, which may subsequently influence how they affect their prey. However, little research investigates the behavioural mechanisms underpinning carnivore response to humans.

Conditional Alternative Protein Splicing Promoted by Inteins from .

Protein splicing is a post-translational process by which an intervening protein, or an intein, catalyzes its own excision from flanking polypeptides, or exteins, coupled to extein ligation. Four inteins interrupt the MCM helicase of the halophile , two of which are mini-inteins that lack a homing endonuclease. Both inteins can be overexpressed in and purified as unspliced precursors; splicing can be induced by incubation with salt.

Intein Inhibitors as Novel Antimicrobials: Protein Splicing in Human Pathogens, Screening Methods, and Off-Target Considerations.

Protein splicing is a post-translational process by which an intervening polypeptide, or intein, catalyzes its own removal from the flanking polypeptides, or exteins, concomitant with extein ligation. Although inteins are highly abundant in the microbial world, including within several human pathogens, they are absent in the genomes of metazoans. As protein splicing is required to permit function of essential proteins within pathogens, inteins represent attractive antimicrobial targets.

An alternative domain-swapped structure of the Pyrococcus horikoshii PolII mini-intein.

Protein splicing is a post-translational process by which an intein catalyzes its own excision from flanking polypeptides, or exteins, concomitant with extein ligation. Many inteins have nested homing endonuclease domains that facilitate their propagation into intein-less alleles, whereas other inteins lack the homing endonuclease (HEN) and are called mini-inteins. The mini-intein that interrupts the DNA PolII of Pyrococcus horikoshii has a linker region in place of the HEN domain that is shorter than the linker in a closely related intein from Pyrococcus abyssi.

Protein Splicing Activity of the PolB-c Intein Is Sensitive to Homing Endonuclease Domain Mutations.

Inteins are selfish genetic elements residing in open reading frames that can splice post-translationally, resulting in the ligation of an uninterrupted, functional protein. Like other inteins, the DNA polymerase B (PolB) intein of the halophilic archaeon has an active homing endonuclease (HEN) domain, facilitating its horizontal transmission. Previous work has shown that the presence of the PolB intein exerts a significant fitness cost on the organism compared to an intein-free isogenic .

Allosteric Influence of Extremophile Hairpin Motif Mutations on the Protein Splicing Activity of a Hyperthermophilic Intein.

Protein splicing is a post-translational process mediated by an intein, whereby the intein excises itself from a precursor protein with concomitant ligation of the two flanking polypeptides. The intein that interrupts the DNA polymerase II in the extreme hyperthermophile has a β-hairpin that extends the central β-sheet of the intein. This β-hairpin is mostly found in inteins from archaea, as well as halophilic eubacteria, and is thus called the extremophile hairpin (EXH) motif.

Methods to Study the Structure and Catalytic Activity of cis-Splicing Inteins.

The autocatalytic process of protein splicing is facilitated by an intein, which interrupts flanking polypeptides called exteins. The mechanism of protein splicing has been studied by overexpression in E. coli of intein fusion proteins with nonnative exteins.

Altered splicing and cytoplasmic levels of tRNA synthetases in SF3B1-mutant myelodysplastic syndromes as a therapeutic vulnerability.

Myelodysplastic syndromes (MDS) are haematopoietic malignancies that are characterised by a heterogeneous clinical course. In recent years, sequencing efforts have uncovered recurrent somatic mutations within RNA splicing factors, including SF3B1, SRSF2, U2AF1 and ZRSR2. The most frequently mutated gene is SF3B1, mutated in 17% of MDS patients.

Coordination of the third step of protein splicing in two cyanobacterial inteins.

The third step of protein splicing is cyclization of Asn coupled to peptide bond cleavage. In two related cyanobacterial inteins, this step is facilitated by Asn or Gln. For a Synechococcus sp.

V67L Mutation Fills an Internal Cavity To Stabilize RecA Mtu Intein.

Inteins mediate protein splicing, which has found extensive applications in protein science and biotechnology. In the Mycobacterium tuberculosis RecA mini-mini intein (ΔΔIhh), a single valine to leucine substitution at position 67 (V67L) dramatically increases intein stability and activity. However, crystal structures show that the V67L mutation causes minimal structural rearrangements, with a root-mean-square deviation of 0.

Intein-Promoted Cyclization of Aspartic Acid Flanking the Intein Leads to Atypical N-Terminal Cleavage.

Protein splicing is a post-translational reaction facilitated by an intein, or intervening protein, which involves the removal of the intein and the ligation of the flanking polypeptides, or exteins. A DNA polymerase II intein from Pyrococcus abyssi (Pab PolII intein) can promote protein splicing in vitro on incubation at high temperature. Mutation of active site residues Cys1, Gln185, and Cys+1 to Ala results in an inactive intein precursor, which cannot promote the steps of splicing, including cleavage of the peptide bond linking the N-extein and intein (N-terminal cleavage).

Does Predation Influence the Seasonal and Diel Timing of Moose Calving in Central Ontario, Canada?

Birth synchrony is well documented among ungulates and is hypothesised to maximize neonate survival, either by minimizing the risk of predation through predator swamping or by synchronising birthing with increased seasonal food availability. We used encapsulated vaginal implant transmitters to locate and capture neonatal moose calves and document the seasonal and diel timing of parturition in two adjacent study areas with different predation pressure in central Ontario, Canada. We tested the hypothesis that predation promotes earlier and more synchronous birth of moose calves.

Salt-Dependent Conditional Protein Splicing of an Intein from Halobacterium salinarum.

An intein from Halobacterium salinarum can be isolated as an unspliced precursor protein with exogenous exteins after Escherichia coli overexpression. The intein promotes protein splicing and uncoupled N-terminal cleavage in vitro, conditional on incubation with NaCl or KCl at concentrations of >1.5 M.

Identification and validation of the dopamine agonist bromocriptine as a novel therapy for high-risk myelodysplastic syndromes and secondary acute myeloid leukemia.

Myelodysplastic syndromes (MDS) represent a broad spectrum of diseases characterized by their clinical manifestation as one or more cytopenias, or a reduction in circulating blood cells. MDS is predominantly a disease of the elderly, with a median age in the UK of around 75. Approximately one third of MDS patients will develop secondary acute myeloid leukemia (sAML) that has a very poor prognosis.

Protein splicing: how inteins escape from precursor proteins.

Inteins are nature's escape artists; they facilitate their excision from flanking polypeptides (exteins) concomitant with extein ligation to produce a mature host protein. Splicing requires sequential nucleophilic displacement reactions catalyzed by strategies similar to proteases and asparagine lyases. Inteins require precise reaction coordination rather than rapid turnover or tight substrate binding because they are single turnover enzymes with covalently linked substrates.

Recent advances in in vivo applications of intein-mediated protein splicing.

Intein-mediated protein splicing has become an essential tool in modern biotechnology. Fundamental progress in the structure and catalytic strategies of cis- and trans-splicing inteins has led to the development of modified inteins that promote efficient protein purification, ligation, modification and cyclization. Recent work has extended these in vitro applications to the cell or to whole organisms.

Internal disulfide bond acts as a switch for intein activity.

Inteins are intervening polypeptides that catalyze their own removal from flanking exteins, concomitant to the ligation of the exteins. The intein that interrupts the DP2 (large) subunit of DNA polymerase II from Methanoculleus marisnigri (Mma) can promote protein splicing. However, protein splicing can be prevented or reduced by overexpression under nonreducing conditions because of the formation of a disulfide bond between two internal intein Cys residues.

Graphically characterizing the movement of a rabid striped skunk epizootic across the landscape in northwestern Wyoming.

A striped skunk (Mephitis mephitis) rabies epizootic in northwestern Wyoming was studied from the Index Case in 1988 to the last case in 1993, and possibly is the first rabies epizootic in a previously rabies-free zone monitored from beginning to end. The 843 km(2) study area comprised skunk habitat along 90 km of Shoshone River's floodplain from Bighorn Lake upstream to Cody. Of 1,015 skunks tested, 215 were rabies-positive.

Intramolecular disulfide bond between catalytic cysteines in an intein precursor.

Protein splicing is a self-catalyzed and spontaneous post-translational process in which inteins excise themselves out of precursor proteins while the exteins are ligated together. We report the first discovery of an intramolecular disulfide bond between the two active-site cysteines, Cys1 and Cys+1, in an intein precursor composed of the hyperthermophilic Pyrococcus abyssi PolII intein and extein. The existence of this intramolecular disulfide bond is demonstrated by the effect of reducing agents on the precursor, mutagenesis, and liquid chromatography-mass spectrometry (LC-MS) with tandem MS (MS/MS) of the tryptic peptide containing the intramolecular disulfide bond.

Structural and mutational studies of a hyperthermophilic intein from DNA polymerase II of Pyrococcus abyssi.

Protein splicing is a precise self-catalyzed process in which an intein excises itself from a precursor with the concomitant ligation of the flanking polypeptides (exteins). Protein splicing proceeds through a four-step reaction but the catalytic mechanism is not fully understood at the atomic level. We report the solution NMR structures of the hyperthermophilic Pyrococcus abyssi PolII intein, which has a noncanonical C-terminal glutamine instead of an asparagine.

1H, 13C, and 15N NMR assignments of the Pyrococcus abyssi DNA polymerase II intein.

Protein splicing is a precise post-translational process mediated by inteins. Inteins are intervening proteins that cleave themselves from a precursor protein while joining the flanking sequences. Here we report the (15)N, (13)C, and (1)H chemical shift assignments of the intein from DNA polymerase II of Pyrococcus abyssi (Pab PolII intein), which has been recombinantly overexpressed and isotopically labeled.

Canonical protein splicing of a class 1 intein that has a class 3 noncanonical sequence motif.

A Thermobifida fusca intein has two characteristics of class 3 inteins: a noncontiguous covariant Trp-Cys-Thr triplet and a Ser flanking its C terminus. However, it has Cys at position one, characteristic of class 1 inteins. Splicing does not require the internal Cys, which may instead coordinate the active site.

Mechanism of protein splicing of the Pyrococcus abyssi lon protease intein.

Protein splicing is a post-translational process by which an intervening polypeptide, the intein, excises itself from the flanking polypeptides, the exteins, coupled to ligation of the exteins. The lon protease of Pyrococcus abyssi (Pab) is interrupted by an intein. When over-expressed as a fusion protein in Escherichia coli, the Pab lon protease intein can promote efficient protein splicing.