RAD51 is required for propagation of the germinal nucleus in Tetrahymena thermophila

• Published in: Genetics (Austin) Vol. 154; no. 4; pp. 1587 - 1596
• Main Authors: Marsh, T C, Cole, E S, Stuart, K R, Campbell, C, Romero, D P
• Format: Journal Article
• Language: English
• Published: United States Genetics Society of America 01-04-2000
• Subjects: Animals; Base Sequence; Cell Cycle - genetics; Conjugation, Genetic; Deoxyribonucleic acid; DNA; DNA Primers; DNA Replication; DNA-Binding Proteins - physiology; Enzymes; Escherichia coli; Gene Expression Regulation; Genetics; Pharmacology; RAD51 gene; Rad51 protein; Rad51 Recombinase; recA protein; Tetrahymena thermophila; Tetrahymena thermophila - genetics; Yeast
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/154.4.1587

RAD51, the eukaryote homolog of the Escherichia coli recA recombinase, participates in homologous recombination during mitosis, meiosis, and in the repair of double-stranded DNA breaks. The Tetrahymena thermophila RAD51 gene was recently cloned, and the in vitro activities and induction of Rad51p following DNA damage were shown to be similar to that of RAD51 from other species. This study describes the pattern of Tetrahymena RAD51 expression during both the cell cycle and conjugation. Tetrahymena RAD51 mRNA abundance is elevated during macronuclear S phase during vegetative cell growth and with both meiotic prophase and new macronuclear development during conjugation. Gene disruption of the macronuclear RAD51 locus leads to severe abnormalities during both vegetative growth and conjugation. rad51 nulls divide slowly and incur rapid deterioration of their micronuclear chromosomes. Conjugation of two rad51 nulls leads to an arrest early during prezygotic development (meiosis I). We discuss the potential usefulness of the ciliates' characteristic nuclear duality for further analyses of the potentially unique roles of Tetrahymena RAD51.