Comparison of histone methylation modification of Bemisia tabaci with and without Hamiltonella defensa
Grinded tissue in liquid nitrogen or collected the cultured cells in centrifuge tube andthen washed with 1X PBS buffer. After centrifugation and removing the supernatant, 1%formaldehyde in PBS buffer was used to cross-link DNA and proteins for about 10min at 37 .After that, 0.125 M of glycine was used to stop the crosslinking reaction. the cells werewashed with precooled PBS with 0.5% bovine serum and by PBS supplemented with proteaseinhibitor compound (PIC). The cells were collected by centrifugation at 850 rpm for 3 minafter each wash. The cells were resuspended in 200 l ice-cold lyses buffer (1% SDS, 10mM EDTA, 50 mM Tris-HCl, pH 7.5 plus PIC) and then thawed on ice for 10 min to allow celllyses. The cell lysate was sonicated using Bioruptor Pico to generate chromatin fragmentsof size range from 100 to 800 bp. One-tenth of the sonicated chromatin sample was separatedfor input control. The remaining chromatin was immunoprecipitated in ChIP dilution buffer(1% Triton, 2 mM EDTA, 150 mM NaCl, 20 mM Tris-HCl, pH 7.5) with 4 g of antibody thathas been pre-incubated with protein A/G magnetic beads (Invitrogen; 10003D). Theimmunoprecipitation reaction was incubated overnight at 4 C and the beads were washedtwice with each of the following buffers at 4 C: RIPA buffer (10 mM Tris, 1 mM EDTA, 0.1%SDS, 0.1% Na-deoxycholate, 0.1% Triton X-100); RIPA buffer plus 0.3 M NaCl; LiCl buffer(0.25 M LiCl, 0.5% NP-40, 0.5% Na-deoxycholate) and TE buffer. The captured DNA and inputcontrol sample were reverse cross-linked by eluting the beads with elution buffer (1% SDS,0.1 M NaHCO3) at 65 C for 2 h, respectively. The eluted DNA was purified byphenol-chloroform extraction and precipitated with ethanol and glycogen. The obtained DNAwas subjected to library preparation and sequenced on Illumina sequencing platform