• Molecules and Cells
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• v.19 no.2
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• pp.289-293
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• 2005

BAF53 is an actin-related protein that shuttles between nucleus and cytoplasm. In the nucleus, it constitutes an integral component of many chromatin-modifying complexes such as the SWI/SNF, TIP60, TRRAP, and TIP48/49 complexes. BAF53 is essential for growth, but its function remains elusive. BAF53 homologues from yeast to humans have a conserved N-terminal motif, MS_(G/A)(G/A)__(V/L)YGG, which is unique to these proteins. Previously we showed that over-expression of an N-terminal deletion mutant of BAF53 ($BAF53_-{\Delta}N$) reduced the viability of HEK293 and HeLa cells. When we replaced the serine 2 and tyrosine 6 of this N-terminal motif with alanine, over-expression of the alanine-replaced BAF53 strongly impaired the growth of HEK293 cells whereas replacement with aspartate/glutamate had no effect. The alanine-replaced BAF53 mutants also stimulated p53-dependent transcription, in which the SWI/SNF and TRRAP complexes are involved. Our results demonstrate that serine 2 and tyrosine 6 play important roles in BAF53 activity.

• Animal cells and systems
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• v.16 no.3
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• pp.183-189
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• 2012

It has been suggested that chromatin is organized into the stable structures that provide fundamental units of chromosome architecture in interphase mammalian cells. The stable structures of chromatin can be visualized as replication foci when replicating DNA is labeled with thymidine analogs. Previously, we showed that the chromosome territory expanded after BAF53 knockdown. In this study, we found that BAF53 is required for the formation of replication foci. DNA replication was not impaired in BAF53 knockdown cells, suggesting that the decrease in the number of replication foci is due to disintegration of replication foci, but not suppression of DNA replication. The attractive forces that maintain structural integrity of replication foci could be disrupted by BAF53 knockdown, and it may be responsible, at least in part, for the expansion of chromosome territories after BAF53 knockdown.

• Molecules and Cells
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• v.24 no.2
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• pp.288-293
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• 2007

The conversion of mitotic chromosome into interphase chromatin consists of at least two separate processes, the decondensation of the mitotic chromosome and the formation of the higher-order structure of interphase chromatin. Previously, we showed that depletion of BAF53 led to the expansion of chromosome territories and decompaction of the chromatin, suggesting that BAF53 plays an essential role in the formation of higher-order chromatin structure. We report here that BAF53 is associated with mitotic chromosomes during mitosis. Immunostaining with two different anti-BAF53 antibodies gave strong signals around the DNA of mitotic preparations of NIH3T3 cells and mouse embryo fibroblasts (MEFs). The immunofluorescent signals were located on the surface of mitotic chromosomes prepared by metaphase spread. BAF53 was also found in the mitotic chromosome fraction of sucrose gradients. Association of BAF53 with mitotic chromosomes would allow its rapid activation on the chromatin upon exit from mitosis.

• Animal cells and systems
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• v.13 no.4
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• pp.405-409
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• 2009

When DNA double-strand breaks (DSBs) were induced in mammalian cells, many DNA damage response proteins are accumulated at damage sites to form nuclear foci called IR-induced foci. Although the formation of foci has been shown to promote repair efficiency, the structural organization of chromatin in foci remains obscure. BAF53 is an actin-related protein which is required for maintenance of chromosome territory. In this study, we show that the formation of IR-induced foci by $\gamma$-H2AX and 53BP1 were reduced when BAF53 is depleted, while DSB- activated ATM pathway and the phosphorylation of H2AX remains intact after DNA damage in BAF53 knockdown cells. We also found that DSB repair efficiency was largely compromised in BAF53 knockdown cells. These results indicate that BAF53 is critical for formation of foci by $\gamma$-H2AX decorated chromatin at damage sites and the structural organization of chromatin in foci is an important factor to achieve the maximum efficiency of DNA repair.

• Molecules and Cells
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• v.38 no.9
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• pp.789-795
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• 2015

A chromosome territory is composed of chromosomal subdomains. The internal structure of chromosomal subdomains provides a structural framework for many genomic activities such as replication and DNA repair, and thus is key to determining the basis of their mechanisms. However, the internal structure and regulating proteins of a chromosomal subdomain remains elusive. Previously, we showed that the chromosome territory expanded after BAF53 knockdown. Because the integrity of chromosomal subdomains is a deciding factor of the volume of a chromosome territory, we examined here the effect of BAF53 knockdown on chromosomal subdomains. We found that BAF53 knockdown led to the disintegration of histone H2B-GFP-visualized chromosomal subdomains and BrdU-labeled replication foci. In addition, the size of DNA loops measured by the maximum fluorescent halo technique increased and became irregular after BAF53 knockdown, indicating DNA loops were released from the residual nuclear structure. These data can be accounted for by the model that BAF53 is prerequisite for maintaining the structural integrity of chromosomal subdomains.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.2
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• pp.55-65
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• 1999

AF(anaerobic filter)/BAF(biological aerated filter) system and UASB(upflow anaerobic sludge blanket)/BAF system, of which system effluents were recirculated to the anaerobic reactors in each system, were operated in order to investigate the performance in simultaneous removal of organics and nitrogen in high-strength dairy wastewater. Advanced anaerobic treatment processes of AF and UASB were evaluated on applicability as pre-denitrification reactors, and BAF was also evaluated on the performance in oxidizing the remaining organics and ammonia nitrogen. At system HRTs of 4.0 to 4.5 days and recirculation ratios of one to three, the AF/BAF system could achieve more than 99% of organics removals and 64 to 78% of total nitrogen removals depending upon the recirculation ratio. Although the UASB/BAF system also showed more than 99% of organics removals, total nitrogen removals in the UASB/BAF system were 53 to 66% which are lower than those in the AF/BAF system at the corresponding recirculation ratios. Optimum recirculation ratios considering simultaneous removal of organics and nitrogen and cost-effectiveness, were in the range of two to three. The upflow AF packed with crossflow module media, as a primary treatment of the anaerobic reactor/BAF system, showed better performances in denitrification, SS removals, and gas production than the UASB. Higher loading rate of suspended solids from the UASB increased the backwashing times in the following BAF. Especially, at a recirculation ratio of three in the UASB/BAF system, the increase in head loss due to clogging in the BAF caused frequent backwashing, at least once d day. The BAF showed the high nitrification efficiency of average 99.2% and organics removals more than 90% at organics loading rate less than $1.4KgCOD/m^3/d$ and $COD/NH_3-N$ ratio less than 6.4. It was proved that the simplified anaerobic reactor/BAF system could maximize the organics removal and achieve high nitrogen removal efficiencies through recirculation of system effluents to the anaerobic reactor. The AF/BAF system can, especially, be a cost effective and competitive alternative for the simultaneous removal of organics ana nitrogen from wastewaters.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.2
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• pp.77-84
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• 2011

This study was conducted to develop a novel combined system of a hybrid rotating biological contactor (RBC) process that was composed of an attached- and suspended- biomass reactor, followed by a settler and a biological aerated filter (BAF) column to treat a high strength slaughter wastewater. Long term influences of organic and nitrogen loading rates were investigated to see how the combined system worked in terms of the removal efficiency. A synthetic wastewater containing a pork cutlet steak source (commercially available) and swine blood was used to feed the combined system. The hybrid RBC process showed excellent removals: about 95% for soluble COD and 85% for ammonium nitrogen. However, the unsettled solids seriously deteriorated the removal efficiency of total COD (TCOD) and total nitrogen (TN) in the RBC process. A significant fraction of the TCOD and suspended solids (SS) was further removed in the BAF column although the effluent quality was still unsatisfactory, giving TCOD 300 mg/L, SS 180 mg/L and TN 59 mg/L. An addition of polyaluminium chloride into the RBC effluent improved the performance of the settler and BAF, producing an excellent quality of final effluent; TCOD 16.5 mg/L, SS 0 mg/L, TN 55.5 mg/L, TP 1.3 mg/L. Therefore, it was confirmed that the combined system of hybrid RBC and BAF could treat a high strength slaughter wastewater excellently.

• Tuberculosis and Respiratory Diseases
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• v.53 no.5
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• pp.510-518
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• 2002

Background : Bronchial anthracofibrosis (BAF) is a dark black or brown pigmentation of multiple large bronchi associated with a fibrotic stenosis or obliteration that is incidentally found during a diagnostic bronchoscopy some reporters have suggested endobronchial tuberculosis or tuberculous lymphadenitis as a possible cause of BAF. However, some BAF patients do not have any medical history of tuberculosis. The aim of this study was to elucidate the clinical features of simple BAF patients, which were not associated with tuberculosis. Methods : We reviewed the patients' charts retrospectiely and interviewed all BAF patients who were followed up for 1 year or more. Among the 114 BAF patients, 43 patents (38 %) had no associated tuberculosis, cancer and pneumoconiosis. The clinical characteristics, radiological findings and associated pulmonary diseases of these patients were evaluated. Results : Most patients were non-smokers, old aged, housewifes who resided in a farming village. The common respiratory symptoms were dyspnea, cough and hemoptysis. The predominant X-ray findings were a multiple bronchial wall thickening(89%), bronchial narrowing or atelectasis (76%) and a mediastinal lymph node enlargement with/without calcification (78%). Pulmonary function test usually showed mild obstructive ventilatory abnormalities but no patient showed a restrictive ventilatory pattern and the patients were frequently affected with chronic bronchitis(51%), post-obstructive pneumonia(40%) and chronic asthma(4%). Conclusion : Because BAF is frequently associated with chronic bronchitis and obstructive pneumonia as well as tuberculosis, a careful clinical evaluation and accurate differential diagnosis is more essential than empirical anti-tuberculous medication.