Quantum jumps of saturation level rigidity and anomalous oscillations of level number variance in the semiclassical spectrum of a modified Kepler problem.

We observe numerically, and explain analytically, a previously unknown phenomenon of quantum-Hall-like jumps in saturation spectral rigidity in the semiclassical spectrum of a modified Kepler problem as a function of the interval center. These jumps correspond to integer decreases of the radial winding numbers in classical periodic motion. We also observe and explain single-harmonic-dominated oscillations of the level number variance with the width of the energy interval. The level number variance becomes effectively zero for the interval widths defined by the frequency of the shortest periodic orbit. This signifies that there are virtually no variations from sample to sample in the number of levels on such intervals.

CTCF interacts with the lytic HSV-1 genome to promote viral transcription.

CTCF is an essential chromatin regulator implicated in important nuclear processes including in nuclear organization and transcription. Herpes Simplex Virus-1 (HSV-1) is a ubiquitous human pathogen, which enters productive infection in human epithelial and many other cell types. CTCF is known to bind several sites in the HSV-1 genome during latency and reactivation, but its function has not been defined. Here, we report that CTCF interacts extensively with the HSV-1 DNA during lytic infection by ChIP-seq, and its knockdown results in the reduction of viral transcription, viral genome copy number and virus yield. CTCF knockdown led to increased H3K9me3 and H3K27me3, and a reduction of RNA pol II occupancy on viral genes. Importantly, ChIP-seq analysis revealed that there is a higher level of CTD Ser2P modified RNA Pol II near CTCF peaks relative to the Ser5P form in the viral genome. Consistent with this, CTCF knockdown reduced the Ser2P but increased Ser5P modified forms of RNA Pol II on viral genes. These results suggest that CTCF promotes HSV-1 lytic transcription by facilitating the elongation of RNA Pol II and preventing silenced chromatin on the viral genome.

Persistence of strong correlations in the energy spectrum of a separable Hamiltonian system: the rectangular box.

The variance of the number of levels in an energy interval around a level with large quantum numbers (semiclassical quantization) is studied for a particle in a rectangular box. Sampling involves changing the ratio of the rectangle's sides while keeping the area constant. For sufficiently narrow intervals, one finds the usual linear growth with the width of the interval. For wider intervals, the variance undergoes large, nondecaying oscillations around what is expected to be the saturation value. These oscillations can be explained as a superposition of just a few harmonics that correspond to the shortest periodic orbits in the rectangle. The analytical and numerical results are in excellent agreement.