A role for Piwi and piRNAs in germ cell maintenance and transposon silencing in Zebrafish.
Piwi proteins specify an animal-specific subclass of the Argonaute family that, in vertebrates, is specifically expressed in germ cells. We demonstrate that zebrafish Piwi (Ziwi) is expressed in both the male and the female gonad and is a component of a germline-specifying structure called nuage. Loss of Ziwi function results in a progressive loss of germ cells due to apoptosis during larval development. In animals that have reduced Ziwi function, germ cells are maintained but display abnormal levels of apoptosis in adults. In mammals, Piwi proteins associate with approximately 29-nucleotide-long, testis-specific RNA molecules called piRNAs. Here we show that zebrafish piRNAs are present in both ovary and testis. Many of these are derived from transposons, implicating a role for piRNAs in the silencing of repetitive elements in vertebrates. Furthermore, we show that piRNAs are Dicer independent and that their 3' end likely carries a 2'O-Methyl modification.
Houwing
Saskia
S
Hubrecht Laboratory, Uppsalalaan 8, Utrecht, Netherlands.
Kamminga
Leonie M
LM
Berezikov
Eugene
E
Cronembold
Daniela
D
Girard
Angélique
A
van den Elst
Hans
H
Filippov
Dmitri V
DV
Blaser
Heiko
H
Raz
Erez
E
Moens
Cecilia B
CB
Plasterk
Ronald H A
RH
Hannon
Gregory J
GJ
Draper
Bruce W
BW
Ketting
René F
RF
D000818:Animals; D004625:Embryo, Nonmammalian / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D005260:Female; D016678:Genome; D005854:Germ Cells / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D008297:Male; D010053:Ovary / Q000166:cytology; D034622:RNA Interference; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D018626:Retroelements; D013737:Testis / Q000166:cytology; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000378:metabolism*
D022661:RNA, Untranslated; D016601:RNA-Binding Proteins; D018626:Retroelements; D029961:Zebrafish Proteins; C472855:piwil1 protein, zebrafish