BACKGROUND: The Synurophyceae is one of most important photosynthetic stramenopile algal lineages in freshwater ecosystems. They are characterized by siliceous scales covering the cell or colony surface and possess plastids of red-algal secondary or tertiary endosymbiotic origin. Despite their ecological and evolutionary significance, the relationships amongst extant Synurophyceae are unclear, as is their relationship to most other stramenopiles. RESULTS: Here we report a comparative analysis of plastid genomes sequenced from five representative synurophycean algae. Most of these plastid genomes are highly conserved with respect to genome structure and coding capacity, with the exception of gene re-arrangements and partial duplications at the boundary of the inverted repeat and single-copy regions. Several lineage-specific gene loss/gain events and intron insertions were detected (e.g., cemA, dnaB, syfB, and trnL). CONCLUSIONS: Unexpectedly, the cemA gene of Synurophyceae shows a strong relationship with sequences from members of the green-algal lineage, suggesting the occurrence of a lateral gene transfer event. Using a molecular clock approach based on silica fossil record data, we infer the timing of genome re-arrangement and gene gain/loss events in the plastid genomes of Synurophyceae.
- MeSH
- fylogeneze MeSH
- genetická variace * MeSH
- genom plastidový * MeSH
- genomika * MeSH
- genová dávka MeSH
- Heterokontophyta genetika MeSH
- konformace nukleové kyseliny MeSH
- kruhová DNA genetika MeSH
- molekulární evoluce MeSH
- obrácené repetice genetika MeSH
- RNA transferová chemie genetika MeSH
- sekvence nukleotidů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
UNLABELLED: DiGeorge syndrome (DGS) presents with a wide spectrum of thymic pathologies. Nationwide neonatal screening programs of lymphocyte production using T-cell recombination excision circles (TREC) have repeatedly identified patients with DGS. We tested what proportion of DGS patients could be identified at birth by combined TREC and kappa-deleting element recombination circle (KREC) screening. Furthermore, we followed TREC/KREC levels in peripheral blood (PB) to monitor postnatal changes in lymphocyte production. METHODS: TREC/KREC copies were assessed by quantitative PCR (qPCR) and were related to the albumin control gene in dry blood spots (DBSs) from control (n = 56), severe immunodeficiency syndrome (SCID, n = 10) and DGS (n = 13) newborns. PB was evaluated in DGS children (n = 32), in diagnostic samples from SCID babies (n = 5) and in 91 controls. RESULTS: All but one DGS patient had TREC levels in the normal range at birth, albeit quantitative TREC values were significantly lower in the DGS cohort. One patient had slightly reduced KREC at birth. Postnatal DGS samples revealed reduced TREC numbers in 5 of 32 (16%) patients, whereas KREC copy numbers were similar to controls. Both TREC and KREC levels showed a more pronounced decrease with age in DGS patients than in controls (p < 0.0001 for both in a linear model). DGS patients had higher percentages of NK cells at the expense of T cells (p < 0.0001). The patients with reduced TREC levels had repeated infections in infancy and developed allergy and/or autoimmunity, but they were not strikingly different from other patients. In 12 DGS patients with paired DBS and blood samples, the TREC/KREC levels were mostly stable or increased and showed similar kinetics in respective patients. CONCLUSIONS: The combined TREC/KREC approach with correction via control gene identified 1 of 13 (8%) of DiGeorge syndrome patients at birth in our cohort. The majority of patients had TREC/KREC levels in the normal range.
- MeSH
- biotest MeSH
- DiGeorgeův syndrom diagnóza genetika imunologie MeSH
- dítě MeSH
- kojenec MeSH
- kruhová DNA genetika MeSH
- kultivované buňky MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- lidé MeSH
- mladiství MeSH
- novorozenec MeSH
- novorozenecký screening * MeSH
- předškolní dítě MeSH
- syndromy imunologické nedostatečnosti diagnóza genetika imunologie MeSH
- T-lymfocyty imunologie MeSH
- těžká kombinovaná imunodeficience diagnóza genetika imunologie MeSH
- Check Tag
- dítě MeSH
- kojenec MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- novorozenec MeSH
- předškolní dítě MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
HMGB1 is an architectural protein in chromatin, acting also as a signaling molecule outside the cell. Recent reports from several laboratories provided evidence that a number of both the intracellular and extracellular functions of HMGB1 may depend on redox-sensitive cysteine residues of the protein. In this study we demonstrate that redox state of HMGB1 can significantly modulate the ability of the protein to bind and bend DNA, as well as to promote DNA end-joining. We also report a high affinity binding of histone H1 to hemicatenated DNA loops and DNA minicircles. Finally, we show that reduced HMGB1 can readily displace histone H1 from DNA, while oxidized HMGB1 has limited capacity for H1 displacement. Our results suggested a novel mechanism for the HMGB1-mediated modulation of histone H1 binding to DNA. Possible biological consequences of linker histones H1 replacement by HMGB1 for the functioning of chromatin are discussed.
- MeSH
- chromatin genetika metabolismus MeSH
- exprese genu MeSH
- genetické vektory chemie MeSH
- histony genetika metabolismus MeSH
- konkatenovaná DNA genetika metabolismus MeSH
- kruhová DNA genetika metabolismus MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- oxidace-redukce MeSH
- protein HMGB1 genetika metabolismus MeSH
- rekombinantní proteiny genetika metabolismus MeSH
- skot MeSH
- vazba proteinů MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
