Differential expression of the mouse U1a and U1b SnRNA genes is not dependent on sequence differences in the octamer motif.
The mouse U1b SnRNA gene is expressed in only a limited range of cell types, whereas the U1a SnRNA gene is expressed in all cells. These two genes differ in the sequence of the octamer motif, which plays a critical role in SnRNA gene regulation. We show that the U1b octamer binds the octamer-binding protein Oct-1 with higher affinity than does the U1a octamer in both U1b-expressing and -non-expressing cell lines and tissues. Moreover, the U1b octamer can direct a higher level of gene expression than the U1a octamer when linked to a heterologous promoter and introduced into a non-U1b-expressing cell line. Hence the tissue-specific expression of the U1b gene is not determined by the failure of its octamer motif to bind Oct-1 or the weak affinity of this binding.
Lea
I
I
Department of Biochemistry, University College and Middlesex School of Medicine, London, U.K.
Moore
H D
HD
Latchman
D S
DS
D000818:Animals; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D051863:Host Cell Factor C1; D066298:In Vitro Techniques; D051379:Mice; D008969:Molecular Sequence Data; D050811:Octamer Transcription Factor-1; D012342:RNA, Small Nuclear / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; C497693:Hcfc1 protein, mouse; D051863:Host Cell Factor C1; D050811:Octamer Transcription Factor-1; C494166:Pou2f1 protein, mouse; D012342:RNA, Small Nuclear; D014157:Transcription Factors