title: The multifunctional RNA-binding protein La is required for mouse development and for the establishment of embryonic stem cells.
abstract: The La protein is a target of autoantibodies in patients suffering from Sjögren's syndrome, systemic lupus erythematosus, and neonatal lupus. Ubiquitous in eukaryotes, La functions as a RNA-binding protein that promotes the maturation of tRNA precursors and other nascent transcripts synthesized by RNA polymerase III as well as other noncoding RNAs. La also associates with a class of mRNAs that encode ribosome subunits and precursors to snoRNAs involved in ribosome biogenesis. Thus, it was surprising that La is dispensable in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, the organisms from which it has been characterized most extensively. To determine whether La is essential in mammals and if so, at which developmental stage it is required, mice were created with a disrupted La gene, and the offspring from La+/-intercrosses were analyzed. La-/- offspring were detected at the expected frequency among blastocysts prior to implantation, whereas no nullizygotes were detected after implantation, indicating that La is required early in development. Blastocysts derived from La+/- intercrosses yielded 38 La+/+ and La+/- embryonic stem (ES) cell lines but no La-/- ES cell lines, suggesting that La contributes a critical function toward the establishment or survival of ES cells. Consistent with this, La-/- blastocyst outgrowths revealed loss of the inner cell mass (ICM). The results indicate that in contrast to the situation in yeasts, La is essential in mammals and is one of a limited number of genes required as early as the development of the ICM.
authors.affiliation: Laboratory of Molecular Growth Regulation, National Institute of Child Health and Human Development, 31 Center Drive, Bldg. 31, Rm. 2A25, Bethesda, MD 20892-2426, USA.
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Park
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Kohn
authors.forename: Monique W
authors.initials: MW
authors.lastname: Bruinsma
authors.forename: Claire
authors.initials: C
authors.lastname: Vech
authors.forename: Robert V
authors.initials: RV
authors.lastname: Intine
authors.forename: Stacy
authors.initials: S
authors.lastname: Fuhrmann
authors.forename: Alex
authors.initials: A
authors.lastname: Grinberg
authors.forename: Ipsita
authors.initials: I
authors.lastname: Mukherjee
authors.forename: Paul E
authors.initials: PE
authors.lastname: Love
authors.forename: Minoru S
authors.initials: MS
authors.lastname: Ko
authors.forename: Melvin L
authors.initials: ML
authors.lastname: DePamphilis
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Maraia
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism; D002460:Cell Line; D004247:DNA / Q000235:genetics; D005260:Female; D047109:Fetal Development / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D000097585:SS-B Antigen
chemical_list: D001324:Autoantigens; D004247:DNA; D012333:RNA, Messenger; D012261:Ribonucleoproteins; D000097585:SS-B Antigen