SignificanceThe chromatin remodeling activities of the FACT (facilitates chromatin transactions) complex are required for many cellular functions, including transcription, DNA replication, and repair. Here, we demonstrate that the two FACT subunits, SSRP1 and SPT16, are also required for genome-wide DNA demethylation and regulation of gene imprinting during Arabidopsis reproduction. Without FACT, Arabidopsis seeds undergo abnormal development and exhibit aberrant DNA hypermethylation, including at imprinting control region loci. We show that FACT associates with the DEMETER (DME) DNA demethylase, facilitating DNA demethylation at over half of DME’s targets, specifically those which reside in heterochromatin. These results provide insight into upstream events in the DNA demethylation pathway and reveal the importance of chromatin remodeling for DNA demethylation during Arabidopsis reproduction.

We present a novel active imaging approach that uses optimized wide band filtered illumination to obtain multi-spectral reflectance information. Our optimization algorithm utilizes light source and camera spectral information in order to maximize the signal strength and the robustness to noise. Through the use of active wide band illumination, our system can obtain material reflectance information in the presence of moderate (indoor) unknown ambient illumination. Our method is very simple and does not require special equipment. It can be used by photographers to obtain material properties in uncontrolled environment and to synthesize captured scenes under arbitrary illumination.Keywords Multi-spectral imaging · Multiplexed illumination Problem, Contribution and LimitationsWe seek a very simple approach to multi-spectral imaging to be used by photographers in everyday environments withThis work was done while Cui Chi and Hyunjin Yoo were visiting students at Microsoft Research Asia.

The DEMETER (DME) DNA glycosylase catalyzes genome-wide DNA demethylation and is required for endosperm genomic imprinting and embryo viability. Targets of DMEmediated DNA demethylation reside in small, euchromatic, AT-rich transposons and at the boundaries of large transposons, but how DME interacts with these diverse chromatin states is unknown. The STRUCTURE SPECIFIC RECOGNITION PROTEIN 1 (SSRP1), subunit of the chromatin remodeler FAcilitates Chromatin Transactions (FACT), was previously shown to be involved in the DME-dependent regulation of genomic imprinting in Arabidopsis endosperm. Therefore, to investigate the interaction between DME and chromatin, we focused on the activity of the two FACT subunits, SSRP1 and SUPPRESSOR of TY16 (SPT16), during reproduction in Arabidopsis. We find that FACT co-localizes with nuclear DME in vivo, and that DME has two classes of target sites, the first being euchromatic and accessible to DME, but the second, representing over half of DME targets, requiring the action of FACT for DME-mediated DNA demethylation genomewide. Our results show that the FACT-dependent DME targets are GCrich heterochromatin domains with high nucleosome occupancy enriched with H3K9me2 and H3K27me1. Further, we demonstrate that heterochromatin-associated linker histone H1 specifically mediates the requirement for FACT at a subset of DME-target loci. Overall, our results demonstrate that FACT is required for DME targeting by facilitating its access to heterochromatin.

Fast track article for IS&T International Symposium on Electronic Imaging 2020: Image Quality and System Performance proceedings.

Depth maps captured by active sensors (e.g., ToF cameras and Kinect) typically suffer from poor spatial resolution, considerable amount of noise, and missing data. To overcome these problems, we propose a novel depth map up-sampling method which increases the resolution of the original depth map while effectively suppressing aliasing artifacts. Assuming that a registered high-resolution texture image is available, the cost-volume filtering framework is applied to this problem. Our experiments show that cost-volume filtering can generate the high-resolution depth map accurately and efficiently while preserving discontinuous object boundaries, which is often a challenge when various state-of-the-art algorithms are applied.