title: Peri-implantation lethality in mice lacking the Sm motif-containing protein Lsm4.
abstract: Small nuclear ribonucleoproteins (snRNPs) are particles present only in eukaryotic cells. They are involved in a large variety of RNA maturation processes, most notably in pre-mRNA splicing. Several of the proteins typically found in snRNPs contain a sequence signature, the Sm domain, conserved from yeast to mammals. By using a promoter trap strategy to target actively transcribed loci in murine embryonic stem cells, a new murine gene encoding an Sm motif-containing protein was identified. Database searches revealed that it is the mouse orthologue of Lsm4p, a protein found in yeast and human cells and putatively associated with U6 snRNA. Introduction of the geo reporter gene cassette under the control of the murine Lsm4 (mLsm4) endogenous promoter showed that the gene was ubiquitously transcribed in embryonic and adult tissues. The insertion of the geo cassette disrupted the mLsm4 allele, and homozygosity for the mutation led to a recessive embryonic lethal phenotype. mLsm4-null zygotes survived to the blastocyst stages, implanted into the uterus, but died shortly thereafter. The early death of mLsm4p-null mice suggests that the role of mLsm4p in splicing is essential and cannot be compensated by other Lsm proteins.
authors.affiliation: Max Planck Institut für Biochemie, 82152 Martinsried, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Hirsch
authors.forename: T
authors.initials: T
authors.lastname: Oohashi
authors.forename: M
authors.initials: M
authors.lastname: Ahmad
authors.forename: S
authors.initials: S
authors.lastname: Stamm
authors.forename: R
authors.initials: R
authors.lastname: Fässler
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D010064:Embryo Implantation; D005314:Embryonic and Fetal Development; D005260:Female; D005313:Fetal Death; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012342:RNA, Small Nuclear / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D017411:Ribonucleoproteins, Small Nuclear / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012568:Schizosaccharomyces / Q000235:genetics; D016415:Sequence Alignment; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013234:Stem Cells / Q000502:physiology; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: C485751:LSM4 protein, human; C403621:Lsm4 protein, mouse; D012342:RNA, Small Nuclear; D011993:Recombinant Fusion Proteins; D017411:Ribonucleoproteins, Small Nuclear