Presynaptic CK2 promotes synapse organization and stability by targeting Ankyrin2

The precise regulation of synapse maintenance is critical to the development and function of neuronal circuits. Using an in vivo RNAi screen targeting the Drosophila kinome and phosphatome, we identify 11 kinases and phosphatases controlling synapse stability by regulating cytoskeletal, phospholipid, or metabolic signaling. We focus on casein kinase 2 (CK2) and demonstrate that the regulatory (β) and catalytic (α) subunits of CK2 are essential for synapse maintenance. CK2α kinase activity is required in the presynaptic motoneuron, and its interaction with CK2β, mediated cooperatively by two N-terminal residues of CK2α, is essential for CK2 holoenzyme complex stability and function in vivo. Using genetic and biochemical approaches we identify Ankyrin2 as a key presynaptic target of CK2 to maintain synapse stability. In addition, CK2 activity controls the subcellular organization of individual synaptic release sites within the presynaptic nerve terminal. Our study identifies phosphorylation of structural synaptic components as a compelling mechanism to actively control the development and longevity of synaptic connections.     

Preadapted for invasiveness: do species traits or their plastic response to shading differ between invasive and non‐invasive plant species in their native range?

Aim Species capable of vigorous growth under a wide range of environmental conditions should have a higher chance of becoming invasive after introduction into new regions. High performance across environments can be achieved either by constitutively expressed traits that allow for high resource uptake under different environmental conditions or by adaptive plasticity of traits. Here we test whether invasive and non‐invasive species differ in presumably adaptive plasticity. Location Europe (for native species); the rest of the world and North America in particular (for alien species). Methods We selected 14 congeneric pairs of European herbaceous species that have all been introduced elsewhere. One species of each pair is highly invasive elsewhere in the world, particularly so in North America, whereas the other species has not become invasive or has spread only to a limited degree. We grew native plant material of the 28 species under shaded and non‐shaded conditions in a common garden experiment, and measured biomass production and morphological traits that are frequently related to shade tolerance and avoidance. Results Invasive species had higher shoot–root ratios, tended to have longer leaf‐blades, and produced more biomass than congeneric non‐invasive species both under shaded and non‐shaded conditions. Plants responded to shading by increasing shoot–root ratios and specific leaf area. Surprisingly, these shade‐induced responses, which are widely considered to be adaptive, did not differ between invasive and non‐invasive species. Main conclusions We conclude that high biomass production across different light environments pre‐adapts species to become invasive, and that this is not mediated by plasticities of the morphological traits that we measured.     

Clustering, haplotype diversity and locations of MIC-3: a unique root-specific defense-related gene family in Upland cotton (Gossypium hirsutum L.)

MIC-3 is a recently identified gene family shown to exhibit increased root-specific expression following nematode infection of cotton plants that are resistant to root-knot nematode. Here, we cloned and sequenced MIC-3 genes from selected diploid and tetraploid cotton species to reveal sequence differences at the molecular level and identify chromosomal locations of MIC-3 genes in Gossypium species. Detailed sequence analysis and phylogenetic clustering of MIC-3 genes indicated the presence of multiple MIC-3 gene members in Gossypium species. Haplotypes of a MIC-3 gene family member were discovered by comparative analysis among consensus sequences across genotypes within an individual clade in the phylogram to overcome the problem of duplicated loci in the tetraploid cotton. Deficiency tests of the SNPs delimited six A_t-genome members of the MIC-3 family clustered to chromosome arm 4sh, and one D_t-genome member to chromosome 19. Clustering was confirmed by long-PCR amplification of the intergenic regions using A_t-genome-specific MIC-3 primer pairs. The clustered distribution may have been favored by selection for responsiveness to evolving disease and/or pest pressures, because large variants of the MIC-3 gene family may have been recovered from small physical areas by recombination. This could give a buffer against selection pressure from a broad range of pest and pathogens in the future. To our knowledge, these are the first results on the evolution of clustering and genome-specific haplotype members of a unique cotton gene family associated with resistant response against a major pathogen.     

The endocrinology of puberty and reproductive functioning in female cotton-top tamarins (Saguinus oedipus) under varying social conditions

Sexual maturation and fertility were assessed in fourteen cotton-top tamarin (Saguinus oedipus) females under various social conditions. Six tamarin females (20-28 mo of age) showed a suppression of fertility while living with their families. Hormonal profiles demonstrated low, acyclic levels of urinary luteinizing hormone (LH) and estrone-conjugates (E1C). A rapid onset of ovarian and pituitary cyclicity occurred when four of the six females were removed from their families and paired with an unrelated male. In one female, an ovulatory LH peak occurred as early as eight days after pairing and resulted in conception and full-term pregnancy. Two of the six females were housed in total isolation for 30 days following their removal from the family and prior to pairing. Gradual increases in hormone concentrations occurred during isolation; however, there was no ovarian cyclicity until each female was paired with an unrelated male. In all six females, conception occurred before or as a result of the third ovulatory cycle. Partial isolation of a 36-mo-old female resulted in elevated LH and E1C levels, but cyclicity was not observed until the female was paired with an unrelated male. These findings indicate that removal of a female from the family alone does not initiate ovarian cycling. Sexual maturation, or puberty, occurs in female tamarins living with their families between 15 and 17 mo of age when mean LH and E1C levels began to increase. However, when a female is removed and paired at 9 mo of age with an unrelated male, elevated levels of LH and E1C may be seen by 10 and 11 mo of age. Our findings indicate that a suppression of fertility occurs in cotton-top tamarins living with their families, but that reproductive suppression does not affect the process of sexual maturation. Both removal from the family environment and stimulation by an unrelated male tamarin were necessary to induce normal reproductive activity. An acceleration of puberty occurred when a female tamarin was removed from her family early in development and paired with a male.     

Evolutionary conservation of the human homologue of the yeast cell cycle control gene cdc2 and assignment of Cd2 to chromosome 10

Summary The human homologue of the fission yeast Schizosaccharomyces pombe cell cycle control gene cdc2 has been assigned to chromosome 10. DNA hybridization reveals that this gene is highly conserved in vertebrates. The human CDC2 gene probe detects a simple two-allele polymorphism in Taq1-digested DNA.