MRNA Expression Profiles of Macronuclear Development in Oxytricha trifallax Implicate Scores of Functionally and Evolutionarily Diverse DNA and RNA Binding Proteins in the Program

ABSTRACT: As part of sexual reproduction, the stichotrichous ciliate Oxytricha trifallax orchestrates a remarkable transformation of one of the newly formed germline micronuclear genomes, in which hundreds of thousands of gene pieces are stitched together, excised from chromosomes, and amplified dozens of times, to yield a functional somatic macronuclear genome composed of ~16,000 distinct DNA molecules that typically encode a single gene. Little is known about the proteins that carry out this process. We profiled mRNA expression as a functional of macronuclear development and identified hundreds of mRNAs preferentially expressed at specific times during the program. We find that a disproportionate number of these mRNAs encode proteins that are involved in DNA and RNA functions. Many mRNAs preferentially expressed during macronuclear development have paralogs that are not differentially expressed during development or are expressed at different times, including many components of RNA polymerase II and homologous recombination complexes, suggesting that gene duplication and functional specialization were a key source of evolutionary innovation. While many mRNAs preferentially expressed during macronuclear development encode proteins with no recognizable homolog, hundreds encode proteins that are well-conserved, including a disproportionate number with links to germline function or development in multicellular lineages. These analyses have thus identified scores of factors that may have ancient roles in sexual propagation, germline specialization and differentiation, in addition to dozens of novel factors with striking expression patterns, some of which likely evolved to carry out these extraordinary DNA manipulations.

ORGANISM(S): Oxytricha trifallax

PROVIDER: GSE86081 | GEO | 2017/01/13

SECONDARY ACCESSION(S): PRJNA340200

REPOSITORIES: GEO