OBJECTIVE: To explore the role of small nuclear noncoding RNA 7SK in embryonic stem cell (ESCs) proliferation and the value of 7SK as a target for early diagnosis and treatment for primordial dwarfism (PD). METHODS: ESC line R1 was transfected with the CRISPR/Cas9 system, and sequencing of the PCR product and glycerol gradient analysis were performed to identify novel 7SK deletion mutations. A lentivirus system was used to knock down cyclin-dependent kinase 9 (CDK9) in clones with 7SK deletion mutations, and the effect of CDK9 knockdown on the protein level of cell division cycle 6 (CDC6) was analyzed with Western blotting. RESULTS: We identified a novel deletion mutation of 7SK at 128-179 nt in the ESCs, which resulted in deficiency of cell proliferation. 7SK truncation at 128-179 nt significantly reduced the protein expressions of La-related protein 7 (LARP7) and CDC6. CONCLUSIONS 7SK truncation at 128-179 nt can significantly impair proliferation of ESCs by downregulating CDC6. 7SK is a key regulator of proliferation and mediates the growth of ESCs through a mechanism dependent on CDK9 activity, suggesting the value of 7SK truncation at 128-179 nt as a potential target for early diagnosis and treatment of PD.
Cell Cycle Proteins ; Cell Proliferation ; Embryonic Stem Cells/metabolism* ; HeLa Cells ; Humans ; Nuclear Proteins ; Positive Transcriptional Elongation Factor B/metabolism* ; RNA, Long Noncoding/genetics* ; RNA-Binding Proteins ; Ribonucleoproteins ; Transcription Factors