RNA-Seq of mus musculus
To construct the small RNA library, the RNA sample of 0.21 g was subjected to polyacrylamide gel electrophoresis with bands representing small RNAs of 1830 nt selected  and recycled. The connection 3 adaptor system was prepared under the reaction conditions of 70  for 2 min and then 25  for 2 h; the RT primer was added at 65  for 15 min, ramped 5 to 4 C at a rate of 0.3 C/sec. Finally, the 5' adaptor mix system was prepared at 70  for 2 min and then 25  for 1 h. In the reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, the First Strand Master Mix and Super Script II (Invitrogen) were used in the  reverse transcription at 42  for 1 h and 70  for 15 min; several rounds of PCR amplification with PCR Primer Cocktail and PCR Master Mix were performed to enrich the cDNA fragments at 95  for 3 min, followed by 1518 cycles of 98  for 20 s, 56  for 15 s, and 72  for 15 s with an extension at 72  for 10 min, and finally held at 4 . The PCR products were recovered and purified with PAGE gel with the recycled PCR products dissolved in EB solution. Double stranded PCR products were thermally denatured and cyclized by splint  oligonucleotide sequences. Single stranded circular DNA (ssCir DNA) was used as the final  library. Library was validated on the Agilent Technologies 2100 Bioanalyzer. Under the action of phi29 enzyme, the library formed more than 300 replicated DNA nanospheres, and the DNA nanoball (DNB) obtained were arranged in the mesh pores on the sequencing chip.