Functional characterization of a human histone gene cluster duplication

Histones are the major protein component of nucleosomes, and de novo histone synthesis is essential for packaging newly replicated DNA into chromatin. As a result, histone gene expression is exquisitely and functionally coupled with DNA replication. Vastly divergent organisms such as yeast, fly and human all demonstrate the phylogenetically conserved propensity to maintain clustering of histone genes at one or more genomic loci. Although specific mechanisms are unclear, clustering is presumed to be important for common stringent transcriptional control of these genes at the G1/S phase transition. In this study, we describe a genomic duplication of the human histone gene cluster located at chromosome 1q21, which effectively doubles the previously known size and gene number of that cluster. The duplication persists in all examined tissues and cell lines, and the duplicated genes are transcriptionally active. Levels of messenger RNAs for duplicated histone H4 genes are high relative to those for non-duplicated H4 genes. Our data suggest that transcriptionally robust histone H4 genes may have been preferentially duplicated during evolution

An architectural perspective of cell-cycle control at the G1/S phase cell-cycle transition

A prominent role for the execution of cell cycle and growth regulatory mechanisms within the three-dimensional context of nuclear architecture is becoming increasingly evident. Signaling pathways and regulatory networks that govern activation and suppression of genes controlling proliferation are functionally integrated for the organization and assembly of transcriptional machinery in nuclear microenvironments. The transcriptional activation of histone genes at the G1/S phase transition (S-point) is temporarily, functionally, and spatially distinct from transcriptional mechanisms at the restriction point (R-point). The spatial distinction in R-point versus S-point control is the localization of clustered histone gene loci at cajal bodies, which is modulated during the cell cycle. Histone nuclear factor P (HiNF-P), the principal factor mediating H4 histone gene transcription, is the final link in the signaling cascade that is initiated with growth factor dependent induction of cyclin E/CDK2 kinase activity at the R-point and culminates in the NPAT-mediated activation of histone H4 genes through HiNF-P at the G1/S phase cell-cycle transition

Coordinate control and selective expression of the full complement of replication-dependent histone H4 genes in normal and cancer cells

The replication of eukaryotic genomes necessitates the coordination of histone biosynthesis with DNA replication at the onset of S phase. The multiple histone H4 genes encode identical proteins, but their regulatory sequences differ. The contributions of these individual genes to histone H4 mRNA expression have not been described. We have determined, by real-time quantitative PCR and RNase protection, that the human histone H4 genes are not equally expressed and that a subset contributes disproportionately to the total pool of H4 mRNA. Differences in histone H4 gene expression can be attributed to observed unequal activities of the H4 gene promoters, which exhibit variations in gene regulatory elements. The overall expression pattern of the histone H4 gene complement is similar in normal and cancer cells. However, H4 genes that are moderately expressed in normal cells are sporadically silenced in tumor cells with compensation of expression by other H4 gene copies. Chromatin immunoprecipitation analyses and in vitro DNA binding assays indicated that 11 of the 15 histone H4 genes interact with the cell cycle regulatory histone nuclear factor P, which forms a complex with the cyclin E/CDK2-responsive co-regulator p220(NPAT). These 11 H4 genes account for 95% of the histone H4 mRNA pool. We conclude that the cyclin E/CDK2/p220(NPAT)/histone nuclear factor P signaling pathway is the principal regulator of histone H4 biosynthesis

Functional architecture of the nucleus: organizing the regulatory machinery for gene expression, replication and repair

The organization and sorting of regulatory information for transcription, replication and repair depends on components of nuclear architecture. It is necessary, therefore, to understand cellular processes within the context of intranuclear microenvironments that mediate the focal assembly of the machinery for transcription, replication and repair and which facilitate the orchestration of these essential processes. Here, we discuss how nuclear anatomy supports the temporal and spatial coordination of regulatory protein recruitment for combinatorial control

HiNF-P Directly Links the Cyclin E/CDK2/p220(NPAT) Pathway to Histone H4 Gene Regulation at the G(1)/S Phase Cell Cycle Transition

Genome replication in eukaryotic cells necessitates the stringent coupling of histone biosynthesis with the onset of DNA replication at the G(1)/S phase transition. A fundamental question is the mechanism that links the restriction (R) point late in G(1) with histone gene expression at the onset of S phase. Here we demonstrate that HiNF-P, a transcriptional regulator of replication-dependent histone H4 genes, interacts directly with p220(NPAT), a substrate of cyclin E/CDK2, to coactivate histone genes during S phase. HiNF-P and p220 are targeted to, and colocalize at, subnuclear foci (Cajal bodies) in a cell cycle-dependent manner. Genetic or biochemical disruption of the HiNF-P/p220 interaction compromises histone H4 gene activation at the G(1)/S phase transition and impedes cell cycle progression. Our results show that HiNF-P and p220 form a critical regulatory module that directly links histone H4 gene expression at the G(1)/S phase transition to the cyclin E/CDK2 signaling pathway at the R point

Improving the Positive Predictive Value of Non-Invasive Prenatal Screening (NIPS).

We evaluated performance characteristics of a laboratory-developed, non-invasive prenatal screening (NIPS) assay for fetal aneuploidies. This assay employs massively parallel shotgun sequencing with full automation. GC sequencing bias correction and statistical smoothing were performed to enhance discrimination of affected and unaffected pregnancies. Maternal plasma samples from pregnancies with known aneuploidy status were used for assay development, verification, and validation. Assay verification studies using 2,085 known samples (1873 unaffected, 69 trisomy 21, 20 trisomy 18, 17 trisomy 13) demonstrated complete discrimination between autosomal trisomy (Z scores >8) and unaffected (Z scores <4) singleton pregnancies. A validation study using 552 known samples (21 trisomy 21, 10 trisomy 18, 1 trisomy 13) confirmed complete discrimination. Twin pregnancies showed similar results. Follow-up of abnormal results from the first 10,000 clinical samples demonstrated PPVs of 98% (41/42) for trisomy 21, 92% (23/25) for trisomy 18, and 69% (9/13) for trisomy 13. Adjustment for causes of false-positive results identified during clinical testing (eg, maternal duplications) improved PPVs to 100% for trisomy 21 and 96% for trisomy 18. This NIPS test demonstrates excellent discrimination between trisomic and unaffected pregnancies. The PPVs obtained in initial clinical testing are substantially higher than previously reported NIPS methods

Perancangan Interior Cafe Salon Di Malang

Malang City has good prospect in the culinary fields such as cafes and salon, because the consumptive lifestyle as become a trend in Malang City. Cafe is often used as a place to gather and meet the culinary needs, while salon is often used as a place to let saturation off and body pampering. These perspectives brings Malang into a need of a space to fulfill consumer consumptive pattern and to release saturation in Malang City. This design uses the concept of "Care and Relax". The aim of this concept is to create a space needed by the people which is a place that provides comfortable, serene and relax interior for the people inside. This concept also functions to give warm athmosphere. The application of care in the design is by proximity, protection, openess, and attention while the application of relax in the design is by calmness, roomy and light