Comparison of sequence and function of the Oct-6 genes in zebrafish, chicken and mouse.
To examine the role of the Oct-6 gene in Schwann cell differentiation we have cloned and characterized the chicken and zebrafish homologues of the mouse Oct-6 gene. While highly homologous in the Pit1-Oct1/2-Unc86 (POU) domain, sequence similarities are limited outside this domain. Both genes are intronless and both proteins lack the amino acid repeats that are a characteristic feature of the mammalian Oct-6 proteins. However as in mammals, the aminoterminal parts of the chicken and zebrafish Oct-6 proteins are essential for transactivation of octamer containing promoters. By immunohistochemistry we have found that the chicken Oct-6 protein is expressed in late embryonic ensheathing Schwann cells of the sciatic nerve and is rapidly downregulated when myelination proceeds. This expression profile in glial cells is identical to that in the mouse and rat. Furthermore the zebrafish Oct-6 homolog is expressed in the posterior lateral nerve at a time when it contains actively myelinating Schwann cells. Thus despite extensive primary sequence divergence among the vertebrate Oct-6 proteins, the expression of the chicken and zebrafish Oct-6 proteins is consistent with the notion that Oct-6 functions as a 'competence factor' in promyelin cells to execute the myelination program.
Levavasseur
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F
MGC, Dept. of Cell Biology and Genetics, Erasmus University Rotterdam, P.O. Box 1738, The Netherlands.
Mandemakers
W
W
Visser
P
P
Broos
L
L
Grosveld
F
F
Zivkovic
D
D
Meijer
D
D
D000595:Amino Acid Sequence; D000825:Animal Structures / Q000196:embryology / Q000294:innervation; D000818:Animals; D002645:Chickens / Q000235:genetics*; D019143:Evolution, Molecular; D005786:Gene Expression Regulation; D015723:Gene Library; D006367:HeLa Cells; D006801:Humans; D051379:Mice / Q000235:genetics*; D008969:Molecular Sequence Data; D009186:Myelin Sheath / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D050816:Octamer Transcription Factor-6; D016366:Open Reading Frames; D050809:POU Domain Factors; D010525:Peripheral Nerves / Q000196:embryology / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012583:Schwann Cells / Q000502:physiology; D013045:Species Specificity; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D015533:Transcriptional Activation; D014162:Transfection; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins
D009419:Nerve Tissue Proteins; D050809:POU Domain Factors; C494178:POU3F1 protein, human; C494180:Pou3f1 protein, mouse; D014157:Transcription Factors; D029961:Zebrafish Proteins; C099994:pou3f1 protein, zebrafish; D050816:Octamer Transcription Factor-6