A Multi-Parameter Analysis of Cellular Coordination of Major Transcriptome Regulation Mechanisms

Abstract

To understand cellular coordination of multiple transcriptome regulation mechanisms, we simultaneously measured transcription rate (TR), mRNA abundance (RA) and translation activity (TA). This revealed multiple quantitative insights. First, the genomic profiles of the three parameters are systematically different in key statistical features. Sequentially more genes exhibit extreme low or high expression values from TR to RA, then to TA. That is, because of cellular coordination of these regulatory mechanisms, sequentially higher levels of gene expression selectivity are achieved as genetic information flow from the genome to the proteome. Second, the contribution of the stabilization-by-translation regulatory mechanism to the cellular coordination process was assessed. The data enabled an estimation of mRNA stability, revealing a moderate but significant positive correlation between the estimated mRNA stability and translation activity. Third, the proportion of a mRNA occupied by un-translated regions (UTR) exhibits a negative relationship with the level of this correlation, and is thus a major determinant of the mode of regulation of the mRNA. High-UTR-proportion mRNAs tend to defy the stabilization-by-translation regulatory mechanism, staying out of the polysome but remaining stable; mRNAs with little UTRs largely follow this regulation. In summary, we quantitatively delineated the relationship among multiple transcriptome regulation parameters, i.e., cellular coordination of corresponding regulatory mechanisms.