Germline-restricted chromosome (GRC) is widespread among songbirds

An unusual supernumerary chromosome has been reported for two related avian species, the zebra and Bengalese finches. This large, germline-restricted chromosome (GRC) is eliminated from somatic cells and spermatids and transmitted via oocytes only. Its origin, distribution among avian lineages, and function were mostly unknown so far. Using immunolocalization of key meiotic proteins, we found that GRCs of varying size and genetic content are present in all 16 songbird species investigated and absent from germline genomes of all eight examined bird species from other avian orders. Results of fluorescent in situ hybridization of microdissected GRC probes and their sequencing indicate that GRCs show little homology between songbird species and contain a variety of repetitive elements and unique sequences with paralogs in the somatic genome. Our data suggest that the GRC evolved in the common ancestor of all songbirds and underwent significant changes in the extant descendant lineages

Genes flanking Xist in mouse and human are separated on the X chromosome in American marsupials

X inactivation, the transcriptional silencing of one of the two X chromosomes in female mammals, achieves dosage compensation of X-linked genes relative to XY males. In eutherian mammals X inactivation is regulated by the X-inactive specific transcript (Xist), a cis-acting non-coding RNA that triggers silencing of the chromosome from which it is transcribed. Marsupial mammals also undergo X inactivation but the mechanism is relatively poorly understood. We set out to analyse the X chromosome in Monodelphis domestica and Didelphis virginiana, focusing on characterizing the interval defined by the Chic1 and Slc16a2 genes that in eutherians flank the Xist locus. The synteny of this region is retained on chicken chromosome 4 where other loci belonging to the evolutionarily ancient stratum of the human X chromosome, the so-called X conserved region (XCR), are also located. We show that in both M. domestica and D. virginiana an evolutionary breakpoint has separated the Chic1 and Slc16a2 loci. Detailed analysis of opossum genomic sequences revealed linkage of Chic1 with the Lnx3 gene, recently proposed to be the evolutionary precursor of Xist, and Fip1, the evolutionary precursor of Tsx, a gene located immediately downstream of Xist in eutherians. We discuss these findings in relation to the evolution of Xist and X inactivation in mammals

Low-Dosage Inhibition of DII4 Signaling Promotes Wound Healing by Inducing Functional Neo-Angiogenesis

Recent findings regarding Dll4 function in physiological and pathological conditions indicate that this Notch ligand may constitute an important therapeutic target. Dll4 appears to be a major anti-angiogenic agent, occupying a central role in various angiogenic pathways. The first trials of anti-Dll4 therapy in mice demonstrated a paradoxical effect, as it reduced tumor perfusion and growth despite leading to an increase in vascular density. This is seen as the result of insufficient maturation of the newly formed vasculature causing a circulatory defect and increased tumor hypoxia. As Dll4 function is known to be closely dependent on expression levels, we envisioned that the therapeutic anti-Dll4 dosage could be modulated to result in the increase of adequately functional blood vessels. This would be useful in conditions where vascular function is a limiting factor for recovery, like wound healing and tissue hypoxia, especially in diabetic patients. Our experimental results in mice confirmed this possibility, revealing that low dosage inhibition of Dll4/Notch signaling causes improved vascular function and accelerated wound healing

Mapping tenascin-C interaction with toll-like receptor 4 reveals a new subset of endogenous inflammatory triggers

Pattern recognition underpins innate immunity; the accurate identification of danger, including infection, injury, or tumor, is key to an appropriately targeted immune response. Pathogen detection is increasingly well defined mechanistically, but the discrimination of endogenous inflammatory triggers remains unclear. Tenascin-C, a matrix protein induced upon tissue damage and expressed by tumors, activates toll-like receptor 4 (TLR4)-mediated sterile inflammation. Here we map three sites within tenascin-C that directly and cooperatively interact with TLR4. We also identify a conserved inflammatory epitope in related proteins from diverse families, and demonstrate that its presence targets molecules for TLR detection, while its absence enables escape of innate immune surveillance. These data reveal a unique molecular code that defines endogenous proteins as inflammatory stimuli by marking them for recognition by TLRs

VISUALIZATION OF CHROMOSOME-SPECIFIC DNA SEQUENCES BY FLUORESCENCE IN SITU HYBRIDIZATION OF MICRODISSECTION DNA PROBES WITH METAPHASE CHROMOSOMES

Presently, suppression of repetitive DNAsequences (chromosomal in situ suppression hybridization, СISS-hybridization) is used to improve the results of fluorescence in situ hybridization (FISH). However, in some cases the suppression cannot be performed, because sufficient amounts of DNAof some species are not available. This article presents a new approach, which allows visualization of a signal from chromosome-specific DNAsequences by means of computer-assisted analysis of FISH images

THE EFFECT OF MULTIDRUG RESISTANCE GENE EXPRESSION ON THE CLINICAL COURSE OF MULTIPLE MYELOMA

Background: Implementation of a proteasome inhibitor bortezomib into treatment of multiple myeloma has helped to improve survival of patients with this malignancy that is characterized by continuous relapsing course as a clinical manifestation of multidrug resistance (MDR). Previous studies have resulted in contradictory data on the effects of various MDR genes expression on efficacy of bortezomib. Aim: To evaluate an impact of MDR1, MRP1, LRP, BCRP gene mRNA expression responsible for the development of MDR in bone marrow aspirates from patients with newly diagnosed multiple myeloma before bortezomib-containing therapy on the clinical course of the disease, response to treatment and overall survival. Materials and methods: MDR gene expression was assessed in a  group of 15  patients with newly diagnosed multiple myeloma Durie-Salmon stage  III before initiation of a bortezomib-based chemotherapeutic regimen. The assessment was done in bone marrow mononuclear cell fraction containing plasmocytes. MDR gene expression was measured by reverse transcription polymerase chain reaction test. Results: MDR gene expression was found in all patients with newly diagnosed multiple myeloma before initiation of cytostatic therapy: MDR1 was expressed in 14 (93%) of patients, MRP1 and LRP  – in 11 (73%), BCRP  – in 15  (100%). There was no difference between patient subgroups with high and low MDR gene expression in their clinical parameters, such as hemoglobin level, erythrocyte counts, total calcium, creatinine, total protein, lactate dehydrogenase, and albumin. At diagnosis of multiple myeloma, only absolute levels of paraprotein were significantly lower in patients with high MDR1 gene expression (31.52±3 vs  44.27±3.62  g/L, p<0.05). After 6  cycles of induction, there was a  significant decrease of paraprotein levels in the group with low MDR1 gene expression (from 44.3±3.6 to 16.8±5.2 g/L, p<0.05). Overall survival was negatively associated with high LRP gene expression only (median of overall survival in patients with high LRP gene expression was 17 months and in those with low expression – 62 months, р<0.05). Conclusion: High expression of MDR genes in patients with newly diagnosed multiple myeloma is not associated with clinical characteristics of the disease but may deteriorate the immediate response to bortezomib-based regimens and overall survival