Isolation and characterization of a peptide containing the site of cleavage of the chick skin collagen alpha 1[I] chain by animal collagenases.

A 36-residue peptide containing the bond cleaved by animal collagenases was isolated from a digest of chick skin collagen α1-CB7 by Staphylococcus V8 protease. This cleavage site peptide, in contrast to the 36-residue α1-CB2, showed no tendency to renature to the triple helical form, as monitored by molecular sieve chromatography and the determination of circular dichroism spectra. These results provide a direct demonstration that the conformation of the α1[I] chain immediately around the collagenase cleavage site in the native molecule must be of a lower degree of helicity than other portions of the chain. This is considered to be an important factor in the collagenase specificity, in providing access to the sensitive bonds, but enzyme binding sites, probably located in the adjacent region(s) of maximum helicity, are also considered necessary to produce the maximum reaction rate.     

A conserved role for the zinc finger polyadenosine RNA binding protein,ZC3H14, in control of poly(A) tail length

The ZC3H14 gene, which encodes a ubiquitously expressed, evolutionarily conserved, nuclear, zinc finger polyadenosine RNA-binding protein, was recently linked to autosomal recessive, nonsyndromic intellectual disability. Although studies have been carried out to examine the function of putative orthologs of ZC3H14 in Saccharomyces cerevisiae, where the protein is termed Nab2, and Drosophila, where the protein has been designated dNab2, little is known about the function of mammalian ZC3H14. Work from both budding yeast and flies implicates Nab2/dNab2 in poly(A) tail length control, while a role in poly(A) RNA export from the nucleus has been reported only for budding yeast. Here we provide the first functional characterization of ZC3H14. Analysis of ZC3H14 function in a neuronal cell line as well as in vivo complementation studies in a Drosophila model identify a role for ZC3H14 in proper control of poly(A) tail length in neuronal cells. Furthermore, we show here that human ZC3H14 can functionally substitute for dNab2 in fly neurons and can rescue defects in development and locomotion that are present in dNab2 null flies. These rescue experiments provide evidence that this zinc finger-containing class of nuclear polyadenosine RNA-binding proteins plays an evolutionarily conserved role in controlling the length of the poly(A) tail in neurons.     

Pesticide‐mediated disruption of spotted wing Drosophila flight response to raspberries

The disruption of chemical communication between insects and host plants may take place due to an interference with the signal‐emitting host plant, or the signal‐receiving insect, compromising the signal production and emission, or its reception and processing. Anthropogenic compounds, in general, and pesticides, in particular, may impair the chemical communication that mediates host location by insects. Five different pesticides (the insecticides malathion, pyrethrins and spinetoram, and the fungicides fenhexamid and pyrimethanil) were applied at their field rates to raspberry fruits, or Petri dishes enclosing adult spotted wing Drosophila (SWD; Drosophila suzukii), and the attraction to fruit volatiles was evaluated in a series of two‐choice flight bioassays. The application of raspberry fruit with pesticides did not statistically affect attraction of unexposed adults, with exceptions being the spinetoram treatment, which led to mild insect avoidance, and the pyrethrin treatment, which resulted in slightly preferential attraction. In contrast, adults sublethally exposed to the pesticides had their flight take‐off impaired by the insecticides, but not by the fungicides. Furthermore, all pesticides, and particularly the insecticides, compromised the upwind capture of adults. Thus, the treatment with pesticides may indeed interfere with the flight response of SWD to host volatiles, particularly when the insects were previously exposed to pesticides. These findings are suggestive of the potential for sublethal insecticidal exposures to aid pest control and also provide evidence that pesticide use may compromise sampling/trapping strategies for this pest species that are based on attraction to host volatiles.     

Interaction between the small GTPase Ran/Gsp1p and Ntf2p is required for nuclear transport.

Bidirectional movement of proteins and RNAs across the nuclear envelope requires Ran, a Ras-like GTPase. A genetic screen of the yeast Saccharomyces cerevisiae was performed to isolate conditional alleles of GSP1, a gene that encodes a homolog of Ran. Two temperature-sensitive alleles, gsp1-1 and gsp1-2, were isolated. The mutations in these two alleles map to regions that are structurally conserved between different members of the Ras family. Each mutant strain exhibits various nuclear transport defects. Both biochemical and genetic experiments indicate a decreased interaction between Ntf2p, a factor which is required for protein import, and the mutant GSP1 gene products. Overexpression of NTF2 can suppress the temperature sensitive phenotype of gsp1-1 and gsp1-2 and partially rescue nuclear transport defects. However, overexpression of a mutant allele of NTF2 with decreased binding to Gsp1p cannot rescue the temperature sensitivity of gsp1-1 and gsp1-2. Taken together, these data demonstrate that the interaction between Gsp1p and Ntf2p is critical for nuclear transport.     

Short communication. Identification of developmentally-specific markers in germinating and haustorial stages of Striga hermonthica (Del.) Benth. seedlings

Developmentally-specific markers have been identified in the germinating and haustorial stages of Striga hermonthica seedlings. Four water-soluble proteins, preferentially expressed in germinated seedlings, were microsequenced. An haustorial-specific cDNA clone was isolated by differential screening. Tissue specificity for this clone was assessed by Northern blot hybridization analysis.Key words: Striga hermonthica (Del.) Benth, microsequencing, lipid transfer protein, superoxide dismutase.      

Animal collagenases: specificity of action, and structures of the substrate cleavage site

Two separable hormone entities have been found by exploratory purifications and assay for release of growth hormone (GH) by radioimmunoassay. In recognition of frequent multiple activities of peptide hormones, these two hormonal entities are provisionally designated factors A-GHRH and B-GHRH until they are chemically characterized and their dominant functionality clarified. The A- and B-GHRH designations merely define the assay guiding isolation. Factor A-GHRH was found by filtration on Bio-Gel P-2, and purified over Sephadex G-25 in two partition chromatographic systems, and by Sephadex LH-20. The two partitions and stage LH-20 also differentiated the two active entities. Fractions of A-GHRH were active at 100–200 μg. Factor A-GHRH is inhibited by somatostatin.     

Structure of the Saccharomyces cerevisiae Hrr25:Mam1 monopolin subcomplex reveals a novel kinase regulator

In budding yeast, the monopolin complex mediates sister kinetochore cross‐linking and co‐orientation in meiosis I. The CK1δ kinase Hrr25 is critical for sister kinetochore co‐orientation, but its roles are not well understood. Here, we present the structures of Hrr25 and its complex with the monopolin subunit Mam1. Hrr25 possesses a “central domain” that packs tightly against the kinase C‐lobe, adjacent to the binding site for Mam1. Together, the Hrr25 central domain and Mam1 form a novel, contiguous embellishment to the Hrr25 kinase domain that affects Hrr25 conformational dynamics and enzyme kinetics. Mam1 binds a hydrophobic surface on the Hrr25 N‐lobe that is conserved in CK1δ‐family kinases, suggesting a role for this surface in recruitment and/or regulation of these enzymes throughout eukaryotes. Finally, using purified proteins, we find that Hrr25 phosphorylates the kinetochore receptor for monopolin, Dsn1. Together with our new structural insights into the fully assembled monopolin complex, this finding suggests that tightly localized Hrr25 activity modulates monopolin complex–kinetochore interactions through phosphorylation of both kinetochore and monopolin complex components.