Eukaryotic cells have divided the steps of gene expression between their nucleus and cytoplasm. Protein-encoding genes generate mRNAs in the nucleus and mRNAs undergo transport to the cytoplasm for the purpose of producing proteins. Cap-binding protein (CBP)20 and its binding partner CBP80 have been thought to constitute the cap-binding complex (CBC) that is acquired co-transcriptionally by the precursors of all mRNAs. However, this principle has recently been challenged by studies of nuclear cap-binding protein 3 (NCBP3). Here we submit how NCBP3, as an alternative to CBP20, an accessory to the canonical CBP20−CBP80 CBC, and/or an RNA-binding protein – possibly in association with the exon-junction complex (EJC) – expands the capacity of cells to regulate gene expression.

真核细胞在其细胞核和细胞质之间划分了基因表达的步骤。蛋白质编码基因在细胞核中产生 mRNAs，而 mRNAs 被转运到细胞质以产生蛋白质。帽结合蛋白 (CBP)20 及其结合伙伴 CBP80 被认为构成了帽结合复合物 (CBC)，该复合物由所有 mRNA 的前体共同转录获得。然而，这一原则最近受到核帽结合蛋白 3 (NCBP3) 研究的挑战。在这里，我们提交了 NCBP3，作为 CBP20 的替代品，经典 CBP20-CBP80 CBC 的附件，和/或 RNA 结合蛋白 - 可能与外显子连接复合物 (EJC) 相关 - 扩展细胞的能力调节基因表达。