Malat1 is not an essential component of nuclear speckles in mice.
Malat1 is an abundant long, noncoding RNA that localizes to nuclear bodies known as nuclear speckles, which contain a distinct set of pre-mRNA processing factors. Previous studies in cell culture have demonstrated that Malat1 interacts with pre-mRNA splicing factors, including the serine- and arginine-rich (SR) family of proteins, and regulates a variety of biological processes, including cancer cell migration, synapse formation, cell cycle progression, and responses to serum stimulation. To address the physiological function of Malat1 in a living organism, we generated Malat1-knockout (KO) mice using homologous recombination. Unexpectedly, the Malat1-KO mice were viable and fertile, showing no apparent phenotypes. Nuclear speckle markers were also correctly localized in cells that lacked Malat1. However, the cellular levels of another long, noncoding RNA--Neat1--which is an architectural component of nuclear bodies known as paraspeckles, were down-regulated in a particular set of tissues and cells lacking Malat1. We propose that Malat1 is not essential in living mice maintained under normal laboratory conditions and that its function becomes apparent only in specific cell types and under particular conditions.
RNA Biology Laboratory, RIKEN Advanced Research Institute, Wako, Saitama 351-0198, Japan. nakagawas@riken.jp
Shinichi
S
Nakagawa
Joanna Y
JY
Ip
Go
G
Shioi
Vidisha
V
Tripathi
Xinying
X
Zong
Tetsuro
T
Hirose
Kannanganattu V
KV
Prasanth
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002467:Cell Nucleus / Q000235:genetics*; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D005260:Female; D020869:Gene Expression Profiling; D059765:Homologous Recombination; D017403:In Situ Hybridization; D045586:Intranuclear Inclusion Bodies / Q000235:genetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020411:Oligonucleotide Array Sequence Analysis; D012322:RNA Precursors / Q000235:genetics*; D062085:RNA, Long Noncoding; D012333:RNA, Messenger / Q000235:genetics; D022661:RNA, Untranslated / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
D015415:Biomarkers; C557040:Malat1 long non-coding RNA, mouse; D012322:RNA Precursors; D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D022661:RNA, Untranslated