Z. Ling et al., CONJUGATION-SPECIFIC GENES IN THE CILIATE EUPLOTES-CRASSUS - GENE-EXPRESSION FROM THE OLD MACRONUCLEUS, The Journal of eukaryotic microbiology, 44(1), 1997, pp. 1-11
Following mating or conjugation, the hypotrichous ciliate Euplotes cra
ssus undergoes a massive genome reorganization process. While the natu
re of the rearrangement events has been well studied, little is known
concerning proteins that carry out such processes. As a means of ident
ifying such proteins, differential screening of a developmental cDNA l
ibrary, as well as construction of a cDNA subtraction library, was use
d to isolate genes expressed only during sexual reproduction. Five dif
ferent conjugation-specific genes have been identified that are maxima
lly expressed early in conjugation, during the period of micronuclear
meiosis, which is just prior to macronuclear development and the DNA r
earrangement process. All five genes are retained in the mature macron
ucleus. Micronuclear, macronuclear, and cDNA clones of one gene (conZA
7) have been sequenced, and the results indicate that the gene encodes
a putative DNA binding protein. In addition, the presence of an inter
nal eliminated sequence in the micronuclear copy of the conZA7 gene in
dicates that this conjugation-specific gene is transcribed from the ol
d macronucleus.