Browsing by Author "Fang, W-H"

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3-D Mesh Representation and Retrieval Using Isomap Manifold
(2008)
Chang, Jung-Shiong
;
Shih, Arthur C-C
;
Lin, H-Y
;
Kao, H-F
;
Liao, H-Y Mark
We propose a compact 3-D object representation scheme that can greatly assist the search/retrieval process in a network environment. A 3-D mesh-based object is transformed into a new coordinate frame by using the Isomap (isometric feature mapping) method. During the transformation process, not only the structure of the salient parts of an object will be kept, but also the geometrical relationships will be preserved. From the viewpoint of cognitive psychology, the data distributed on the Isomap manifold can be regarded as a set of significant features of a 3-D mesh-based object. To perform efficient matching, we project the Isomap domain 3-D object onto two different 2-D maps, and the two 2-D feature descriptors are used as the basis to measure the degree of similarity between two 3-D mesh-based objects. Experiments demonstrate that the proposed method in retrieving similar 3-D models is very effective. Most importantly, the proposed 3-D mesh retrieval scheme is still valid even if a 3-D mesh undergoes a mesh simplification process.
YB-1 disrupts mismatch repair complex formation, interferes with MutS alpha recruitment on mismatch and inhibits mismatch repair through interacting with PCNA
(2014-10-23)
Chang, Y-W
;
Mai, R-T
;
Fang, W-H
;
Lin, C-C
;
Chiu, C-C
Y-box binding protein-1 (YB-1) is highly expressed in tumors and it participates in various cellular processes. Previous studies indicated that YB-1 binds to mispaired DNA and interacts with several mismatch repair (MMR)-related factors. However, its role in the MMR system remains undefined. Here, we found that YB-1 represses mutS homolog 6 (MSH6)-containing MMR complex formation and reduces MutS alpha mismatch binding activity by disrupting interactions among MMR-related factors. In an effort to elucidate how YB-1 exerts this inhibitory effect, we have identified two functional proliferating cell nuclear antigen (PCNA)interacting protein (PIP)-boxes that mediate YB-1/PCNA interaction and locate within the C-terminal region of YB-1. This interaction is critical for the regulatory role of YB-1 in repressing MutSa mismatch binding activity, disrupting MutS alpha/PCNA/G/T heteroduplex ternary complex formation and inhibiting in vitro MMR activity. The differential regulation of 3\' and 5\' nick-directed MMR activity by YB-1 was also observed. Moreover, YB-1 overexpression is associated with the alteration of microsatellite pattern and the enhancement of N-methyl-N\'-nitro-N-nitrosoguanidine (MNNG)-induced and spontaneous mutations. Furthermore, upregulation of other PIP-box-containing proteins, such as myeloid cell leukemia-1 (Mcl-1) and inhibitor of growth protein 1b (ING1b), has no impact on MMR complex formation and mutation accumulation, thus revealing the significant effect of YB-1 on regulating the MMR system. In conclusion, our study suggests that YB-1 functions as a PCNA-interacting factor to exert its regulatory role on the MMR process and involves in the induction of genome instability, which may partially account for the oncogenic potential of YB-1.