Systematics of Phyllocnistis leaf-mining moths (Lepidoptera, Gracillariidae) feeding on dogwood (Cornus spp.) in Northeast Asia, with the description of three new species.

During an ongoing DNA-barcoding campaign of the leaf-mining moths that feed on woody plants in Northeast Asia, four lineages of the genus Phyllocnistis (Gracillariidae, Phyllocnistinae) were discovered on dogwood (Cornus spp): P. cornella Ermolaev, 1987 on C. controversa Hemsl. (Japan: Hokkaido) and three new species - one feeding on C. controversa, C. florida L. and C. macrophylla Wall. in Japan (Honshu, Shikoku, Kyushu), a second species on C. macrophylla in China (Yunnan) and a third on Siberian dogwood Cornus alba L. in Russia (Siberia). All these species showed differences in morphology, in the barcode region of the cytochrome c oxidase I gene and in two nuclear genes (histone H3 and 28S ribosomal RNA). No correlation was found between the deep mitochondrial splits observed and the Wolbachia infection pattern. Based on both morphological and molecular evidence, the three recently discovered lineages are described here as new species: P. indistincta Kobayashi & Triberti, sp. n. (Japan), P. saepta Kirichenko, Ohshima & Huang, sp. n. (China) and P. verae Kirichenko, Triberti & Lopez-Vaamonde, sp. n. (Russia). In addition, the authors re-describe the adult morphology of P. cornella, provide the first record of this species from Japan and highlight the diagnostic characters that allow these Cornus-feeding Phyllocnistis species to be distinguished.

Systematics and biology of some species of Micrurapteryx Spuler (Lepidoptera, Gracillariidae) from the Holarctic Region, with re-description of M. caraganella (Hering) from Siberia.

During a DNA barcoding campaign of leaf-mining insects from Siberia, a genetically divergent lineage of a gracillariid belonging to the genus Micrurapteryx was discovered, whose larvae developed on Caragana Fabr. and Medicago L. (Fabaceae). Specimens from Siberia showed similar external morphology to the Palearctic Micrurapteryx gradatella and the Nearctic Parectopa occulta but differed in male genitalia, DNA barcodes, and nuclear genes histone H3 and 28S. Members of this lineage are re-described here as Micrurapteryx caraganella (Hering, 1957), comb. n., an available name published with only a brief description of its larva and leaf mine. Micrurapteryx caraganella is widely distributed throughout Siberia, from Tyumen oblast in the West to Transbaikalia in the East. Occasionally it may severely affect its main host, Caragana arborescens Lam. This species has been confused in the past with Micrurapteryx gradatella in Siberia, but field observations confirm that Micrurapteryx gradatella exists in Siberia and is sympatric with Micrurapteryx caraganella, at least in the Krasnoyarsk region, where it feeds on different host plants (Vicia amoena Fisch. and Vicia sp.). In addition, based on both morphological and molecular evidence as well as examination of type specimens, the North American Parectopa occulta Braun, 1922 and Parectopa albicostella Braun, 1925 are transferred to Micrurapteryx as Micrurapteryx occulta (Braun, 1922), comb. n. with albicostella as its junior synonym (syn. n.). Characters used to distinguish Micrurapteryx from Parectopa are presented and illustrated. These findings provide another example of the potential of DNA barcoding to reveal overlooked species and illuminate nomenclatural problems.

Genetic isolation through time: allochronic differentiation of a phenologically atypical population of the pine processionary moth.

Allochronic speciation refers to a mode of sympatric speciation in which the differentiation of populations is primarily due to a phenological shift without habitat or host change. However, it has been so far rarely documented. The present paper reports on a plausible case of allochronic differentiation between sympatric populations of the pine processionary moth (PPM), Thaumetopoea pityocampa. The PPM is a Mediterranean insect with winter larval development. A phenologically atypical population with early adult activity and summer larval development was detected 10 years ago in Portugal. Mitochondrial and nuclear sequences strongly suggest that the 'summer' individuals are closely related to the sympatric winter population, while microsatellite data show a reduction in allelic richness, a distortion of allelic frequencies and significant genetic differentiation. Moreover, monitoring of adult flights suggests that reproductive activity does not overlap between the summer and winter populations. We postulate that the summer population appeared after a sudden phenological shift of some individuals of the sympatric winter population, leading to a founder effect and complete reproductive isolation. Given that the individuals showing this new phenology are subject to different selection pressures, the observed allochronic differentiation may rapidly lead to deeper divergence.

The polymorphism of the locus control region lying downstream the human IgH locus is restricted to hs1,2 but not to hs3 and hs4 enhancers.

In human, three transcriptional enhancers called hs1,2, hs3 and hs4 were identified downstream the 3' Ig heavy (IgH) locus. We previously reported by PCR and Southern blotting the existence of various allelic forms for the hs1,2 enhancer, one allele being associated with a higher efficiency of switching to IgA in IgA nephropathy (IgAN) patients. Since it is strongly suggested in the mouse that the whole 3' regulatory region is broadly involved in the regulation of class switch recombination (CSR), we wondered if the reported hs1,2 polymorphism was the sole difference possibly accounting for the varying ability to produce non-IgM antibodies in the human population. In this study, we report the absence of additional polymorphism of the hs3 and hs4 enhancers either by using a PCR method or by Southern blotting. DNA sequence analysis confirmed the existence of an invariant core sequence for human hs3 and hs4 enhancers, featuring multiple nuclear factor potential binding sites. In conclusion, human hs3 and hs4 enhancers are not polymorphic, a result that markedly contrasts with the hs1,2 enhancer for which the generation of multiple alleles in both rodents and humans has likely been favored by its central position within a large palindromic region.

RNA surveillance down-regulates expression of nonfunctional kappa alleles and detects premature termination within the last kappa exon.

Random V(D)J junctions would generate nonfunctional and/or out-of-frame sequences in about two-thirds of cases and result in abundant transcripts encoding truncated proteins. Although allelic exclusion at the DNA recombination level ensures that a single allele is functional, the frequent biallelic rearrangements need additional mechanisms to down-regulate aberrant transcripts in those cells with both a functionally and a nonfunctionally rearranged allele. The process of nonsense-mediated decay targets aberrantly rearranged Ig heavy-chain transcripts, but the situation of light-chain mRNAs is more complex, because they do not meet the usual requirements for nonsense-mediated decay and most often lack a spliceable intron downstream of the premature termination. We studied immunoglobulin heavy-chain -/- pro-B cells in which light chain genes get rearranged and expressed in the absence of any selection for the assembly of a functional B cell receptor. Using this model, we show that the whole kappa locus is accessible in pro-B cells and allows the assembly of a broad spectrum of VkappaJkappa segments, most of which are out-of-frame. This model provides an evaluation of the in vivo efficiency of RNA surveillance toward aberrant kappa mRNAs produced in pro-B cells. Our data show that nonfunctional kappa transcripts are excluded from the mature mRNA pool not only by detecting termination in an upstream exon but also by detecting changes in the position of termination within the last exon. Similar mechanisms efficiently down-regulate nonfunctional kappa transcripts arising in normal mature B cells due to the biallelic transcription of rearranged kappa genes.

Expression of a splice variant of the platelet-activating factor receptor transcript 2 in various human cancer cell lines.

Platelet-activating factor receptor (PAF-R) transcripts were analysed by reverse transcriptase-polymerase chain reaction in five human cancer cell lines derived from the breast (BT20, SKBR3 and T47D cells), the pancreas (Miapaca cells) and the bladder (5,637 cells) in order to confirm the existence of a splice variant of the PAF-R transcript 2. After cloning and sequencing, we confirmed its existence in all cell lines. It consisted of the PAF-R transcript 2 lengthening with 82 nucleotides from the 3' end of exon 1 of the PAF-R gene. The role of this elongated form of the tissue-type PAF-R transcript in cell physiology remains to be elucidated.