Abstract
Cell size affects almost all biosynthetic processes by controlling the size of organelles and disrupting the nutrient uptake process. Yeast cells must reach a critical size to be able to enter a new cell cycle stage. Abnormal changes in cell size are often observed under pathological conditions such as cancer disease. Thus, cell size must be strictly controlled during cell cycle progression. Here, we reported that the highly conserved 5′-3′ exonuclease Xrn1 could regulate the gene expression involved in the cell cycle pathway of Cryptococcus neoformans. Chromosomal deletion of XRN1 caused an increase in cell size, defects in cell growth and altered DNA content at 37 °C. RNA-sequencing results showed that the difference was significantly enriched in genes involved in membrane components, DNA metabolism, integration and recombination, DNA polymerase activity, meiotic cell cycle, nuclear division, organelle fission, microtubule-based process and reproduction. In addition, the proportion of the differentially expressed periodic genes was up to 19.8% when XRN1 was deleted, including cell cycle-related genes, chitin synthase genes and transcription factors, indicating the important role of Xrn1 in the control of cell cycle. This work provides insights into the roles of RNA decay factor Xrn1 in maintaining appropriate cell size, DNA content and cell cycle progression.
Highlights
Cell size varies widely between different cell types, but it is narrowly distributed within specific cell types and under specific growth conditions [1]
Our results showed a coordinated control of gene expression by XRN1 to maintain proper expression of cell cycle related genes
Comparing gene gene expression levels in the wild-type and xrn1Δ mutant, we found that 1271 genes were expression levels in the wild-type and xrn1∆ mutant, we found that 1271 genes were significantly altered, significantly altered, of which 92.21% were significantly up-regulated and only 7.79% were of which 92.21% were significantly up-regulated and only 7.79% were significantly down-regulated significantly down-regulated (Figure 5a, Table S3)
Summary
Cell size varies widely between different cell types, but it is narrowly distributed within specific cell types and under specific growth conditions [1]. Cell size control has been studied extensively in a number of different model organisms. In budding yeast Saccharomyces cerevisiae, size control occurs in the G1 phase before START, the point of irreversible commitment to cell division [4,5]. Growing budding yeast and primary mammalian cells with abnormally increased cell size are usually associated with impaired gene induction, abnormal cell cycle progression, and disordered cell signaling [1]. Maintenance of a cell type-specific DNA to cytoplasm ratio is essential for many cellular processes, and beyond this cell type-specific ratio contributes to senescence [1]
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