Matefin, a Caenorhabditis elegans germ line-specific SUN-domain nuclear membrane protein, is essential for early embryonic and germ cell development.
Caenorhabditis elegans mtf-1 encodes matefin, which has a predicted SUN domain, a coiled-coil region, an anti-erbB-2 IgG domain, and two hydrophobic regions. We show that matefin is a nuclear membrane protein that colocalizes in vivo with Ce-lamin, the single nuclear lamin protein in C. elegans, and binds Ce-lamin in vitro but does not require Ce-lamin for its localization. Matefin is detected in all embryonic cells until midembryogenesis and thereafter only in germ-line cells. Embryonic matefin is maternally deposited, and matefin is the first nuclear membrane protein known to have germ line-restricted expression. Animals homozygous for an mtf-1 deletion allele show that matefin is essential for germ line maturation and survival. However, matefin is also required for embryogenesis because mtf-1 (RNAi) embryos die around the approximately 300-cell stage with defects in nuclear structure, DNA content, and chromatin morphology. Down-regulating matefin in mes-3 animals only slightly enhances embryonic lethality, and elimination of UNC-84, the only other SUN-domain gene in C. elegans, has no affect on mtf-1 (RNAi) animals. Thus, mtf-1 mediates a previously uncharacterized pathway(s) required for embryogenesis as well as germ line proliferation or survival.
Fridkin
Alexandra
A
Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Mills
Erez
E
Margalit
Ayelet
A
Neufeld
Esther
E
Lee
Kenneth K
KK
Feinstein
Naomi
N
Cohen
Merav
M
Wilson
Katherine L
KL
Gruenbaum
Yosef
Y
D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D005854:Germ Cells / Q000378:metabolism*; D034882:Lamins / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism; D009685:Nuclear Envelope / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D017434:Protein Structure, Tertiary; D034622:RNA Interference
D029742:Caenorhabditis elegans Proteins; D034882:Lamins; D008562:Membrane Glycoproteins; D009687:Nuclear Proteins; C120560:Unc-84 protein, C elegans