Predictive accuracy of fecal calprotectin for histologic remission in ulcerative colitis.

Background/aims: Accurate assessment of disease activity is crucial for effective management and treatment of ulcerative colitis (UC). This study evaluated the correlation between clinical, endoscopic, and histologic measures of disease activity in UC.

Methods: Clinical, biochemical, endoscopic, and histologic disease activity was studied in 347 patients with UC.

The retrotransposon-derived capsid genes and maintain reproductive capacity.

The human genome contains 24 -like capsid genes derived from deactivated retrotransposons conserved among eutherians. Although some of their encoded proteins retain the ability to form capsids and even transfer cargo, their fitness benefit has remained elusive. Here we show that the -like genes and support reproductive capacity during aging.

The retrotransposon derived capsid genes and maintain reproductive capacity.

The human genome contains 24 -like capsid genes derived from deactivated retrotransposons conserved among eutherians. Although some of their encoded proteins retain the ability to form capsids and even transfer cargo, their fitness benefit has remained elusive. Here we show that the -like genes and support reproductive capacity.

Adverse effects of proton pump inhibitors (PPIs) on the renal system using data mining algorithms (DMAs).

Background: Various adverse drug reactions (ADRs) are associated with proton pump inhibitors (PPIs). However, the effects of PPIs on the renal system are unclear so far. Thus, the main objective of the current study was to identify the possible signals of PPIs in the renal system.

YTHDC2 control of gametogenesis requires helicase activity but not mA binding.

Mechanisms regulating meiotic progression in mammals are poorly understood. The -methyladenosine (mA) reader and 3' → 5' RNA helicase YTHDC2 switches cells from mitotic to meiotic gene expression programs and is essential for meiotic entry, but how this critical cell fate change is accomplished is unknown. Here, we provide insight into its mechanism and implicate YTHDC2 in having a broad role in gene regulation during multiple meiotic stages.

YTHDC2 is essential for pachytene progression and prevents aberrant microtubule-driven telomere clustering in male meiosis.

Mechanisms driving the prolonged meiotic prophase I in mammals are poorly understood. RNA helicase YTHDC2 is critical for mitosis to meiosis transition. However, YTHDC2 is highly expressed in pachytene cells.

yama, a mutant allele of Mov10l1, disrupts retrotransposon silencing and piRNA biogenesis.

Piwi-interacting RNAs (piRNAs) play critical roles in protecting germline genome integrity and promoting normal spermiogenic differentiation. In mammals, there are two populations of piRNAs: pre-pachytene and pachytene. Transposon-rich pre-pachytene piRNAs are expressed in fetal and perinatal germ cells and are required for retrotransposon silencing, whereas transposon-poor pachytene piRNAs are expressed in spermatocytes and round spermatids and regulate mRNA transcript levels.

shani mutation in mouse affects splicing of Spata22 and leads to impaired meiotic recombination.

Recombination is crucial for chromosome pairing and segregation during meiosis. SPATA22, along with its direct binding partner and functional collaborator, MEIOB, is essential for the proper repair of double-strand breaks (DSBs) during meiotic recombination. Here, we describe a novel point-mutated allele (shani) of mouse Spata22 that we isolated in a forward genetic screen.

Distinct 'safe zones' at the nuclear envelope ensure robust replication of heterochromatic chromosome regions.

Chromosome replication and transcription occur within a complex nuclear milieu whose functional subdomains are beginning to be mapped out. Here we delineate distinct domains of the fission yeast nuclear envelope (NE), focusing on regions enriched for the inner NE protein, Bqt4, or the lamin interacting domain protein, Lem2. Bqt4 is relatively mobile around the NE and acts in two capacities.

RNAi drives nonreciprocal translocations at eroding chromosome ends to establish telomere-free linear chromosomes.

The identification of telomerase-negative HAATI (heterochromatin amplification-mediated and telomerase-independent) cells, in which telomeres are superseded by nontelomeric heterochromatin tracts, challenged the idea that canonical telomeres are essential for chromosome linearity and raised crucial questions as to how such tracts translocate to eroding chromosome ends and confer end protection. Here we show that HAATI arises when telomere loss triggers a newly recognized illegitimate translocation pathway that requires RNAi factors. While RNAi is necessary for the translocation events that mobilize ribosomal DNA (rDNA) tracts to all chromosome ends (forming "HAATI" chromosomes), it is dispensable for HAATI maintenance.

mutant mice uncover an essential meiotic function for the ancient RNA helicase YTHDC2.

Mechanisms regulating mammalian meiotic progression are poorly understood. Here we identify mouse YTHDC2 as a critical component. A screen yielded a sterile mutant, '', caused by a missense mutation.

rahu is a mutant allele of Dnmt3c, encoding a DNA methyltransferase homolog required for meiosis and transposon repression in the mouse male germline.

Transcriptional silencing by heritable cytosine-5 methylation is an ancient strategy to repress transposable elements. It was previously thought that mammals possess four DNA methyltransferase paralogs-Dnmt1, Dnmt3a, Dnmt3b and Dnmt3l-that establish and maintain cytosine-5 methylation. Here we identify a fifth paralog, Dnmt3c, that is essential for retrotransposon methylation and repression in the mouse male germline.

A perfect palindrome in the Escherichia coli chromosome forms DNA hairpins on both leading- and lagging-strands.

DNA palindromes are hotspots for DNA double strand breaks, inverted duplications and intra-chromosomal translocations in a wide spectrum of organisms from bacteria to humans. These reactions are mediated by DNA secondary structures such as hairpins and cruciforms. In order to further investigate the pathways of formation and cleavage of these structures, we have compared the processing of a 460 base pair (bp) perfect palindrome in the Escherichia coli chromosome with the same construct interrupted by a 20 bp spacer to form a 480 bp interrupted palindrome.

Telomeric strategies: means to an end.

What really defines a telomere? Telomere literally is an amalgamation of the Greek words "telos," meaning end, and "mer," meaning part. In practice, it refers to the extremities of linear chromosomes. The defining functions of chromosome extremities can be summarized in two main categories.

HAATI survivors replace canonical telomeres with blocks of generic heterochromatin.

The notion that telomeres are essential for chromosome linearity stems from the existence of two chief dangers: inappropriate DNA damage response (DDR) reactions that mistake natural chromosome ends for double-strand DNA breaks (DSBs), and the progressive loss of DNA from chromosomal termini due to the end replication problem. Telomeres avert the former peril by binding sequence-specific end-protection factors that control the access of DDR activities. The latter threat is tackled by recruiting telomerase, a reverse transcriptase that uses an integral RNA subunit to template the addition of telomere repeats to chromosome ends.

H3 k36 methylation helps determine the timing of cdc45 association with replication origins.

Background: Replication origins fire at different times during S-phase. Such timing is determined by the chromosomal context, which includes the activity of nearby genes, telomeric position effects and chromatin structure, such as the acetylation state of the surrounding chromatin. Activation of replication origins involves the conversion of a pre-replicative complex to a replicative complex.