| Summary: | 碩士 === 國立臺灣大學 === 分子醫學研究所 === 95 === In a previous proteomic-based screening for the interacting partners of the transcription elongator FACT, a novel protein, AND-1, was identified. AND-1 (acidic nucleoplasmic DNA-binding protein) is an acidic, nucleoplasmic protein that contains a WD40 domain at amino-terminus and a DNA-binding HMG-box at carboxy-terminus (Kohler et al, 1997). Current findings indicate that AND-1 is a chromatin and nuclear matrix-associated factor. Interestingly, AND-1 possesses a distinct punctate pattern of subnuclear localization especially in mid to late S-phase, which closely correlates with S phase progression in centromere. Further studies using immunostaining and chromatin immunoprecipitation methods pinpointed the centromeric association of AND-1 and its speckled structure. Additionally, interactomic analysis demonstrated that AND-1 might associate with many key factors of the spliceosome complex or RNA-editing enzymes. However, the interacting protein profiles seem slightly different between the soluble and nuclear matrix fractions, suggesting that subcellular pools of AND-1 may possess distinct regulatory or functional roles. Further functional characterization using AND-1 targeting siRNA revealed a possible link of this protein to S-G2 transition and heterochromatin assembling. Abrogation of AND-1 expression also led to enlarge nuclear size as well as increased nuclease accessibility of centromeric α-satellite region. Collectively, these observations imply that AND-1 may be a multifunctional protein that links and coordinates transcriptional and post-transcriptional events, DNA synthesis, as well as centromere organization.
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