Multiple proteins can be assembled from the blueprint of a any given gene, depending on which of the intron sequences (usually removed) and exon sequences (usually retained) within the overall gene sequence are included in the final protein.
Splicing is the part of the gene expression process that determines this outcome, and regulation of splicing is one of the many aspects of cellular biochemistry that becomes disarrayed with age. It is an open question as to how important this is versus other processes in aging, as well as how far downstream from the root causes of aging splicing dysfunction might be, but splicing changes might be relevant in the pace of creation of senescent cells, to pick one example.
Naked mole rat. Image credit: John Brighenti via Flickr, CC BY 2.0
Naked mole-rats are exceptionally long-lived for their size as rodents, and by comparing their biochemistry to that of similarly sized mice, researchers have found a range of mechanisms that might contribute to this longevity.
Naked mole-rats exhibit very good DNA repair; naked mole-rat senescent cells do not secrete damaging and inflammatory signals; cancer suppression mechanisms are very effective; and so forth. Researchers here add stability of splicing regulation to the list. Naked mole-rats do not exhibit the age-related changes in splicing factor expression observed in other mammals, and splicing thus remains stable throughout most of life.
Link: Negligible senescence in naked mole rats may be a consequence of well-maintained splicing regulation
Source: Fight Aging!