WDR55 is a nucleolar modulator of ribosomal RNA synthesis, cell cycle progression, and teleost organ development.
The thymus is a vertebrate-specific organ where T lymphocytes are generated. Genetic programs that lead to thymus development are incompletely understood. We previously screened ethylnitrosourea-induced medaka mutants for recessive defects in thymus development. Here we report that one of those mutants is caused by a missense mutation in a gene encoding the previously uncharacterized protein WDR55 carrying the tryptophan-aspartate-repeat motif. We find that WDR55 is a novel nucleolar protein involved in the production of ribosomal RNA (rRNA). Defects in WDR55 cause aberrant accumulation of rRNA intermediates and cell cycle arrest. A mutation in WDR55 in zebrafish also leads to analogous defects in thymus development, whereas WDR55-null mice are lethal before implantation. These results indicate that WDR55 is a nuclear modulator of rRNA synthesis, cell cycle progression, and embryonic organogenesis including teleost thymus development.
Iwanami
Norimasa
N
Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima, Japan. iwanami@genome.tokushima-u.ac.jp
Higuchi
Tomokazu
T
Sasano
Yumi
Y
Fujiwara
Toshinobu
T
Hoa
Vu Q
VQ
Okada
Minoru
M
Talukder
Sadiqur R
SR
Kunimatsu
Sanae
S
Li
Jie
J
Saito
Fumi
F
Bhattacharya
Chitralekha
C
Matin
Angabin
A
Sasaki
Takashi
T
Shimizu
Nobuyoshi
N
Mitani
Hiroshi
H
Himmelbauer
Heinz
H
Momoi
Akihiro
A
Kondoh
Hisato
H
Furutani-Seiki
Makoto
M
Takahama
Yousuke
Y