Identification of a strand-specific Egr response element binding complex enriched in rat brain.
Multiple members of the Egr family of transcription regulatory factors are rapidly induced in response to neuronal stimulation and share a common double-stranded DNA binding consensus sequence, referred to as the Egr response element. Recent studies have identified transcription regulatory factors that bind preferentially to short segments of single-stranded DNA, rather than the conventional double-stranded versions of regulatory elements. Accordingly, in the present study, we have investigated whether the Egr response element may also be regulated by trans factors that bind to single-stranded versions of this cis element. Using gel-shift studies, we have identified a protein complex that binds selectively to the G-rich strand of the Egr response element. In competition studies, an RNA oligonucleotide containing the corresponding G-rich sequence is approximately 25-fold less potent than its DNA counterpart. This DNA binding complex, referred to as GS1, is present in several regions of the rat brain with highest levels in cerebellum; negligible binding activity was detected in multiple peripheral tissues surveyed. UV cross-linking studies revealed two major protein bands with estimated molecular masses of 36 and 30 kDa. The highly restricted tissue distribution of this complex and its sequence-specific binding properties indicate that GS1 may be involved in regulating transcription directed by the Egr response element in brain.
Taira
E
E
Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, U.S.A.
Baraban
J M
JM
D000818:Animals; D002531:Cerebellum / Q000737:chemistry* / Q000502:physiology; D003432:Cross-Linking Reagents / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics; D004586:Electrophoresis / Q000379:methods; D005816:Genetic Complementation Test; D051381:Rats; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014466:Ultraviolet Rays
D003432:Cross-Linking Reagents; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D014157:Transcription Factors