Oct2 transcription factor of a teleost fish: activation domains and function from an enhancer.
Oct2 transcription factors of the catfish (Ictalurus punctatus) are expressed as alternatively spliced alpha and beta isoforms. Functional analysis revealed an N-terminal glutamine (Q)-rich transactivation domain common to both isoforms of catfish Oct2. A C-terminal proline, serine, threonine (PST)-rich activation domain was identified exclusively in the beta isoform. Activation domains of fish and mammalian Oct2 showed cell type- and species-specific activity correlated with their biochemical composition (Q-rich vs PST-rich). In contrast the activation domains of the aryl hydrocarbon receptor and aryl hydrocarbon receptor nuclear translocator of fish and mammals showed no correlation of activity with biochemical composition or species of origin. Although isolated catfish Oct2 activation domains were unable to drive transcription from a site 1.9kb distal to the promoter, Oct2beta activated transcription from both an IgH enhancer and an array of octamer motifs at this distal position. The properties of catfish Oct2 activation domains differ depending on whether they are studied in isolation or as components of the intact transcription factor.
Department of Biochemistry and Molecular Biology, The Medical University of South Carolina, Charleston, SC 29425, USA.
Christopher C
CC
Cioffi
Richard S
RS
Pollenz
Darlene L
DL
Middleton
Melanie R
MR
Wilson
Norman W
NW
Miller
L
L
William Clem
Gregory W
GW
Warr
David A
DA
Ross
D017398:Alternative Splicing; D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D002397:Catfishes / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D004268:DNA-Binding Proteins; D004742:Enhancer Elements, Genetic; D005803:Genes, Immunoglobulin; D051379:Mice; D027701:Organic Cation Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000075102:Organic Cation Transporter 2; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D018336:Receptors, Aryl Hydrocarbon / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity; D014018:Tissue Distribution; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation
C497397:Arnt protein, mouse; D004268:DNA-Binding Proteins; D027701:Organic Cation Transport Proteins; D000075102:Organic Cation Transporter 2; D020033:Protein Isoforms; D018336:Receptors, Aryl Hydrocarbon; D011993:Recombinant Fusion Proteins; C491012:Slc22a2 protein, mouse; D014157:Transcription Factors; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator