The unique spliceosome signature of human pluripotent stem cells is mediated by SNRPA1, SNRPD1, and PNN
STEM CELL RESEARCH
Authors: Kim, Young-Dae; Lee, Jungwoon; Kim, Han-Seop; Lee, Mi-Ok; Son, Mi-Young; Yoo, Chae Hwa; Choi, Jung-Kyun; Lee, Sang Chul; Cho, Yee Sook
Abstract
Spliceosomes are the core host of pre-mRNA splicing, allowing multiple protein isoforms to be produced from a single gene. Herein, we reveal that spliceosomes are more abundant in human pluripotent stem cells (hPSs), including human embryonic stem cells (hESs) and human induced pluripotent stem cells (hiPSs), than non-hPSs, and their presence is associated with high transcriptional activity. Supportively, spliceosomal components involved in the catalytically active pre-mRNA splicing step were mainly co-localized with hPS spliceosomes. By profiling the gene expression of 342 selected splicing factors, we found that 71 genes were significantly altered during the reprogramming of human somatic cells into hiPSs. Among them, SNRPA1, SNRPD1, and PNNwere significantly up-regulated during the early stage of reprogramming, identified as hub genes by interaction network and cluster analysis. SNRPA1, SNRPD1, or PNNdepletion led to a pronounced loss of pluripotency and significantly blocked hiPS generation. SNRPA1, SNRPD1, and PNN co-localized with the hPS spliceosomes, physically interacted with each other, and positively influenced the appearance of hPS spliceosomes. Our data suggest that SNRPA1, SNRPD1, and PNN are key players in the regulation of pluripotency-specific spliceosome assembly and the acquisition and maintenance of pluripotency. (C) 2017 The Authors. Published by Elsevier B.V.
Analysis of genes for human snRNP Sm-D1 protein and identification of the promoter sequence which shows segmental homology to the promoters of SM-E and U1 snRNA genes
GENE
Authors: Sun, D; Ou, YC; Hoch, SO
Abstract
The Sm core proteins of U1, U2, U4/U6 and U5 snRNPs include B(B1), B'(B2), N(B3), D1, D2, D3, E, F and G polypeptides. We have isolated genomic clones encoding the Sm-DI protein using the Sm-D1 cDNA as probe. Southern blotting and DNA sequencing analysis of these clones revealed the presence of an Sm-D1 multigene family in the human genome. Three gene members have been identified. Two of the genes are without introns and contain mutations compared to the cDNA sequence. They appear to be processed pseudogenes. The third gene, termed SNRPD1, shares 100% identity to the cDNA sequence including both 5'- and 3'-untranslated regions (UTR); it contains three introns. Analysis of the 5'-flanking region of the SNRPD1 gene revealed promoter activity, suggesting this is the functional gene that encodes the Sm-D1 protein. The promoter activity was localized in a 0.38 kb PstI fragment using CAT reporter gene fusion assays. Addition of an SV40 enhancer element did not enhance the transcription directed by that fragment. Sequence comparison of the 0.38 kb promoter sequence with the promoters of the Sm-E gene and UI snRNA genes revealed several homologous motifs, suggesting that genes encoding the snRNP components may be coordinately regulated. (C) 1997 Elsevier Science B.V.