Cells were fixed and stained for BubR1 (are enlarged views of representative kinetochore pairs. Tris buffer. Purified IgG was concentrated with Amicon Ultra-4 device (Millipore) and stored in the presence of 30% glycerol. Additional primary antibodies used in this study are as follows: ACA (gift from Don W. Cleveland, University or college of California at San Diego); anti-CENP-H antibody (ab77207, Abcam); anti-CENP-I rabbit antibody (A303-374A, Bethyl Laboratories Inc.); anti-CENP-F rabbit antibody (ab5, Abcam); anti-CENP-A-pS7 rabbit antibody (A13968, Invitrogen); and anti-Hec1 mouse antibody CIL56 (9G3.23, GeneTex). Anti-FLAG antibody (F1804), anti-tubulin antibody (DM1A, T9026), anti-GFP antibody (G6539), and anti-Mad2 mouse antibody (M8694) were purchased from Sigma. Anti-Aurora B antibody (611082) and anti-BubR1 antibody (612503) were purchased from BD Biosciences. CSPP1 siRNA (synthesized by Qiagen) focusing on to 5-GAAGATTTGCGCAGTGGAC-3 was used, as explained previously (15). Another CSPP1 siRNA purchased from Santa Cruz Biotechnology (sc-77463) was also used in our work. Hec1 siRNA (AAGUUCAAAAGCUGGAUGAUCUU), Aurora B siRNA (AACGCGGCACUUCACAAUUGA), and CENP-F siRNA (AAGAGAAGACCCCAAGUCAUC) were purchased or synthesized in Dharmacon. CENP-H siRNA (CAGAGAGGAUAAAGAUCAUACGACA) and CENP-I siRNA (AACAAACCAUUUCGUGTGAGA) were purchased or synthesized in CIL56 Qiagen. Cell Tradition, Transfection, and Drug Treatments HeLa cells, from American Type Tradition Collection (ATCC), were cultured and managed in advanced Dulbecco’s altered Eagle’s medium (DMEM, Gibco) with 10% fetal bovine serum (FBS, HyClone) and 2 mm glutamine (Gibco) at 37C with 8% CO2. Cells were transfected with plasmids or siRNA (usually 100 nm), using Lipofectamine 2000 (Invitrogen). For mitotic synchronization, cells were clogged at G1/S phase in 2 mm thymidine (Sigma) for 16 h, followed by launch in fresh medium for 7C9 h. In some specific experiments, cells were treated with the indicated inhibitors for another 1 or 2 2 h, wherein 100 ng/ml nocodazole was used to depolymerize MT; 10 ng/ml nocodazole was then applied to generate misaligned kinetochores. Hesperadins was used at 100 nm; MG132 was used at 20 m; and okadaic acid (OA) was used at 100 nm. Immunofluorescence Microscopy and Data Analysis Cells produced on coverslips were fixed with chilly methanol at ?20 C for 3 min or with 3.7% formaldehyde at 37 C for 10 min. After formaldehyde fixation, cells were consequently permeabilized with 0.1% Triton X-100 in CREB5 PBS at space temperature for 10 min. Following a 30-min block in 1% BSA and incubation with main antibodies at space heat for 1 h, cells were incubated with secondary antibodies for another 1 h. After 1 min of staining with 4,6-diamidino-2-phenylindole (DAPI, Sigma), cells were mounted. Images were acquired using Olympus 60/1.42 Strategy APO N objective on an Olympus IX71 microscope (Applied Precision Inc.) or LSM 710 confocal microscope (Carl Zeiss). Deconvoluted images from each focal aircraft were projected into a solitary stack montage using SoftWorx software (Applied Precision). In some cases, images of a single focal aircraft are demonstrated in the numbers. For fluorescence intensity quantification, the kinetochore staining signals were measured with ImageJ software, according to the methods explained previously (8, 23). Live Cell Microscopy and Data Analysis Live cell imaging was performed as explained previously (24, 25). Cells were cultured in CO2-self-employed medium plus 10% FBS and 2 mm glutamine at 37 C. In cell cycle progression imaging, HeLa cells expressing mCherry-H2B and GFP–tubulin were transfected with the indicated siRNA(s) and synchronized. Images were acquired from nuclear envelope breakdown (NEBD) with 3- or 5-min intervals under the Olympus DeltaVision microscope. In the tracking of oscillatory kinetochores round the metaphase plate, siRNA-transfected cells expressing GFP-CENP-B, as kinetochore marker, were imaged every 3 or 10 s under the Olympus DeltaVision microscope or LSM confocal microscope (Carl Zeiss). Sister kinetochore positions of each kinetochore pair were calculated and offered as relative to the mean position of the sister kinetochore center within the imaging CIL56 duration. The amplitude of oscillations were assessed by calculating the standard deviations of relative sister kinetochore positions and sister kinetochore separations. The velocity of sister kinetochore movement along the spindle axis was also determined, as an indication for the pace of kMT plus end turnover. Immunoprecipitation and GST Pulldown For immunoprecipitations, HeLa or HEK293T cells, transfected with indicated plasmids, were collected and lysed in lysis buffer (50 mm Tris-HCl, pH 7.4, 150 mm NaCl, 1 mm EDTA, and 0.1% Triton X-100), in the presence of protease inhibitor mixture (Sigma). After clarification by centrifugation, cell lysates were incubated with FLAG M2 beads or GFP-Trap microbeads at 4 C revolving for 4 h. In immunoprecipitation of endogenous CSPP1, HeLa cell lysates were incubated with IgG or CSPP1 antibody at 4.