Transcriptome analysis of the binucleate ciliate Tetrahymena thermophila cells after mating and re-feeding.

During macronuclear development the five germline chromosomes undergo massive rearrangement, and the entire epigenome is remodeled from an obligate heterochromatic to obligate euchromatic state. The ~180 unique macronuclear chromosomes undergo two development waves of endo-reduplication to achieve a final copy number of ~45C, while the 21 kb rDNA minichromosome is amplified to ~9000C. The first period (endoreplication phase I) involves two rounds of DNA replication and generates an 8 C macronucleus (6–18 h after mating). Upon re-feeding, a second re-replication period (endoreplication phase II) is initiated generating a macronuclear DNA content of 32–64 C. This study focused on RNA expression profile of cell in endoreplication phase II. Overall design: Cell of different mating types were induced to conjugate by mixng after overnight starvation (19 hours). RNA was isolated at 2 hours after refeeding cells that were mated for 24 hours (endoreplication phase II). Non-mating cells that were starved for 24 hours and then refed for 2 hours were used as control (vegetative cell cycle, early S phase).