An investigation into the role of human mesoderm induction-early response 1 (hMI-ER1) in regulating a histone acetyltransferase, a chromatin remodeling enzyme

xmi-er 1, Xenopus mesoderm induction early response 1 gene, was initially discovered as a developmentally regulated gene that was transcribed in response to fibroblast growth factor (FGF). FGF family members are involved in mitogenesis, differentiation, and angiogenesis (Baird and Klagsbrun, 1991). Additional studies revealed that XMI-ER1 functioned as a potent transcriptional activator, where the N-terminalacidic domain was responsible for the activity. The human orthologue of mi-er 1, hmi-er 1, was also isolated and was shown to be 91% similar to xmi-er 1. Further analysis revealed that hmi-er 1 expression levels were upregulated in breast carcinoma cell lines and tissue, and that it acted as a transcriptional repressor by interaction with a histone deacetylase, HDAC1, through its ELM2 domain (Paterno et al., 1998; Paterno et al., 2002; Ding et al., 2003). HDACs and histone acetyltransferases (HATs) are enzymes that play a very important role in modifying histones, altering chromatin, and regulating transcription. -- In this study, we further investigated the role of hMI-ER1 in the regulation of transcription. We demonstrated that hMI-ER1B, an isoform ofhMI-ER1, inhibited the HAT activity of the coactivator Creb-binding protein (CBP). hMI-ER1β physically interacted with CBP, and the interaction led to the inhibition of CBP HAT activity. The interaction required a region within aa 1-179 ofhMI-ER1, an area containing several acidic regions. Within the CBP molecule, a region located between aa 1092-2441, which contains a bromodomain, a C/H2 and C/H3 domain, a HAT domain, and a Q rich domain, was required for the interaction. The results indicate that hMI-ER1 interacts with CBP and that it has the potential to play a role in HAT-mediated transcription

The transcriptional cofactor MIER1-beta negatively regulates histone acetyltransferase activity of the CREB-binding protein

Background: Mier1 encodes a novel transcriptional regulator and was originally isolated as a fibroblast growth factor early response gene. Two major protein isoforms have been identified, MIER1 and, which differ in their C-terminal sequence. Previously, we demonstrated that both isoforms recruit histone deacetylase 1 (HDAC1) to repress transcription. To further explore the role of MIER1 in chromatin remodeling, we investigated the functional interaction of MIER1 with the histone acetyltransferase (HAT), Creb-binding protein (CBP). Findings: Using GST pull-down assays, we demonstrate that MIER1 interacts with CBP and that this interaction involves the N-terminal half (amino acids 1-283) of MIER1, which includes the acidic activation and ELM2 domains and the C-terminal half (amino acids 1094-2441) of CBP, which includes the bromo-, HAT, C/H3 and glutamine-rich domains. Functional analysis, using HEK293 cells, shows that the CBP bound to MIER1 in vivo has no detectable HAT activity. Histone 4 peptide binding assays demonstrate that this inhibition of HAT activity is not the result of interference with histone binding. Conclusion: Our data indicate that an additional mechanism by which MIER1 could repress transcription involves the inhibition of histone acetyltransferase activity

Strong Stability and Host Specific Bacterial Community in Faeces of Ponies

The horse, as a hindgut fermenter, is reliant on its intestinal bacterial population for efficient diet utilisation. However, sudden disturbance of this population can result in severe colic or laminitis, both of which may require euthanasia. This study therefore aimed to determine the temporal stability of the bacterial population of faecal samples from six ponies maintained on a formulated high fibre diet. Bacterial 16S rRNA terminal restriction fragment length polymorphism (TRFLP) analyses of 10 faecal samples collected from 6 ponies at regular intervals over 72 hour trial periods identified a significant pony-specific profile (P<0.001) with strong stability. Within each pony, a significantly different population was found after 11 weeks on the same diet (P<0.001) and with greater intra-individual similarity. Total short chain fatty acid (SCFA) concentration increased in all ponies, but other changes (such as bacterial population diversity measures, individual major SCFA concentration) were significant and dependent on the individual. This study is the first to report the extent of stability of microbes resident in the intestinal tract as represented with such depth and frequency of faecal sampling. In doing so, this provides a baseline from which future trials can be planned and the extent to which results may be interpreted

Relationship between molecular pathogen detection and clinical disease in febrile children across Europe: a multicentre, prospective observational study

BackgroundThe PERFORM study aimed to understand causes of febrile childhood illness by comparing molecular pathogen detection with current clinical practice.MethodsFebrile children and controls were recruited on presentation to hospital in 9 European countries 2016-2020. Each child was assigned a standardized diagnostic category based on retrospective review of local clinical and microbiological data. Subsequently, centralised molecular tests (CMTs) for 19 respiratory and 27 blood pathogens were performed.FindingsOf 4611 febrile children, 643 (14%) were classified as definite bacterial infection (DB), 491 (11%) as definite viral infection (DV), and 3477 (75%) had uncertain aetiology. 1061 controls without infection were recruited. CMTs detected blood bacteria more frequently in DB than DV cases for N. meningitidis (OR: 3.37, 95% CI: 1.92-5.99), S. pneumoniae (OR: 3.89, 95% CI: 2.07-7.59), Group A streptococcus (OR 2.73, 95% CI 1.13-6.09) and E. coli (OR 2.7, 95% CI 1.02-6.71). Respiratory viruses were more common in febrile children than controls, but only influenza A (OR 0.24, 95% CI 0.11-0.46), influenza B (OR 0.12, 95% CI 0.02-0.37) and RSV (OR 0.16, 95% CI: 0.06-0.36) were less common in DB than DV cases. Of 16 blood viruses, enterovirus (OR 0.43, 95% CI 0.23-0.72) and EBV (OR 0.71, 95% CI 0.56-0.90) were detected less often in DB than DV cases. Combined local diagnostics and CMTs respectively detected blood viruses and respiratory viruses in 360 (56%) and 161 (25%) of DB cases, and virus detection ruled-out bacterial infection poorly, with predictive values of 0.64 and 0.68 respectively.InterpretationMost febrile children cannot be conclusively defined as having bacterial or viral infection when molecular tests supplement conventional approaches. Viruses are detected in most patients with bacterial infections, and the clinical value of individual pathogen detection in determining treatment is low. New approaches are needed to help determine which febrile children require antibiotics.FundingEU Horizon 2020 grant 668303

Cross validated discriminant function analysis plot for relative FTIR data by pony (both trial periods).

<p>Trained data used in the original validation process are denoted by a cross, whilst test data are denoted by a star. Between the two DF values 99.66% of the total variance was described.</p

Bacterial population diversity indicators: number of TRF, Shannon Diversity Indices and Evenness.

<p>Average and standard error (SE) for each pony within trial period and for each restriction enzyme shown. P¹ values identify significant changes between TP within pony and RE. P² values identify significant differences between ponies, within TP and RE. ns – not significant, * P<0.05; ** P<0.01; *** P<0.001.</p

Dendrogram of Manhattan Distances (relative abundance) from TRFLP data.

<p>10 samples per pony (n = 6) per trial period (1, 2) are represented. Dendrogram coloured by pony and samples clustering by pony and trial period are labelled (eg P1,TP1 represents pony 1 in TP1). i, ii denote first and second clusters within pony and trial period.</p

Concentration (mM) of total and each major SCFA, for each pony and trial period.

<p>P¹ values identify significant changes between TP within pony and each SCFA. P² values identify significant differences between ponies, within TP and each SCFA. ns – not significant, * P<0.05; ** P<0.01; *** P<0.001.</p

Dendrogram of Hamming Distances (binary abundance) from TRFLP data.

<p>10 samples per pony (n = 6) per trial period (1, 2) are represented. Dendrogram coloured by pony and samples clustering by pony and trial period are labelled (eg P1,TP1 represents pony 1 in TP1). i, ii denote first and second clusters within pony and trial period.</p