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Conjugation‐Specific Genes in the Ciliate Euplotes crassus : Gene Expression from the Old Macronucleus
Author(s) -
LING ZHONG,
GHOSH SUSMITA,
JACOBS MARY ELLEN,
KLOBUTCHER LAWRENCE A.
Publication year - 1997
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.1997.tb05682.x
Subject(s) - macronucleus , biology , gene , ciliate , genetics , complementary dna , genome , cdna library , dna , gene duplication
. Following mating or conjugation, the hypotrichous ciliate Euplotes crassus undergoes a massive genome reorganization process. While the nature of the rearrangement events has been well studied, little is known concerning proteins that carry out such processes. As a means of identifying such proteins, differential screening of a developmental cDNA library, as well as construction of a cDNA subtraction library, was used to isolate genes expressed only during sexual reproduction. Five different conjugation‐specific genes have been identified that are maximally expressed early in conjugation, during the period of micronuclear meiosis, which is just prior to macronuclear development and the DNA rearrangement process. All five genes are retained in the mature macronucleus. Micronuclear, macronuclear, and cDNA clones of one gene ( conZ47 ) have been sequenced, and the results indicate that the gene encodes a putative DNA binding protein. In addition, the presence of an internal eliminated sequence in the micronuclear copy of the conZ47 gene indicates that this conjugation‐specific gene is transcribed from the old macronucleus.