{PDOC00037} {PS50090; MYB_LIKE} {PS51294; HTH_MYB} {BEGIN} ******************************************** * Myb-type HTH DNA-binding domain profiles * ******************************************** The myb family can be classified into three groups: the myb-type HTH domain, which binds DNA, the SANT domain, which is a protein-protein interaction module (see ) and the myb-like domain that can be involved in either of these functions. The myb-type HTH domain is a DNA-binding, helix-turn-helix (HTH) domain of ~55 amino acids, typically occurring in a tandem repeat in eukaryotic transcription factors. The domain is named after the retroviral oncogene v-myb, and its cellular counterpart c-myb, which encode nuclear DNA-binding proteins that specifically recognize the sequence YAAC(G/T)G [1,2]. Myb proteins contain three tandem repeats of 51 to 53 amino acids, termed R1, R2 and R3. This repeat region is involved in DNA-binding and R2 and R3 bind directly to the DNA major groove. The major part of the first repeat is missing in retroviral v-Myb sequences and in plant myb-related (R2R3) proteins [3]. A single myb-type HTH DNA-binding domain occurs in TRF1 and TRF2. The 3D-structure of the myb-type HTH domain forms three alpha-helices (see ) [4]. The second and third helices connected via a turn comprise the helix-turn-helix motif. Helix 3 is termed the recognition helix as it binds the DNA major groove, like in other HTHs. Some proteins known to contain a myb-type HTH domain: - Fruit fly myb protein [2]. - Vertebrate myb-like proteins A-myb and B-myb. - Maize anthocyanin regulatory C1 protein, a trans-acting factor which controls the expression of genes involved in anthocyanin biosynthesis. - Maize P protein [5], a trans-acting factor which regulates the biosynthetic pathway of a flavonoid-derived pigment in certain floral tissues. - Arabidopsis thaliana protein GL1/GLABROUS1 [6], required for the initiation of differentiation of leaf hair cells (trichomes). - Maize and barley myb-related proteins Zm1, Zm38 and Hv1, Hv33 [7]. - Yeast BAS1 [8], a transcriptional activator for the HIS4 gene. - Yeast REB1 [9], which recognizes sites within both the enhancer and the promoter of rRNA transcription, as well as upstream of many genes transcribed by RNA polymerase II. - Fission yeast cdc5, a possible transcription factor whose activity is required for cell cycle progression and growth during G2. - Fission yeast myb1, which regulates telomere length and function. - Baker's yeast pre-mRNA-splicing factor CEF1. - Vertebrate telomeric repeat-binding factors 1 and 2 (TRF1/2), which bind to telomeric DNA and are involved in telomere length regulation. We have developed a profile, which has been manually adapted to specifically detect the DNA-binding myb-type HTH domain. A second general profile was developed for detection of the myb-like domain with a high sensitivity. A third profile was developed for the SANT domain (see ). -Sequences known to belong to this class detected by the first profile: ALL. -Other sequence(s) detected in Swiss-Prot: 2. -Sequences known to belong to this class detected by the second profile: ALL, except 25. -Other sequence(s) detected in Swiss-Prot: 2. -Note: The profiles are in competition with one another and with the profile of the SANT domain (see ). -Last update: February 2007 / Profile and text revised; profile added; patterns removed. [ 1] Biedenkapp H., Borgmeyer U., Sippel A.E., Klempnauer K.-H. "Viral myb oncogene encodes a sequence-specific DNA-binding activity." Nature 335:835-837(1988). PubMed=3185713; DOI=10.1038/335835a0 [ 2] Peters C.W.B., Sippel A.E., Vingron M., Klempnauer K.-H. "Drosophila and vertebrate myb proteins share two conserved regions, one of which functions as a DNA-binding domain." EMBO J. 6:3085-3090(1987). PubMed=3121304 [ 3] Stracke R., Werber M., Weisshaar B. "The R2R3-MYB gene family in Arabidopsis thaliana." Curr. Opin. Plant. Biol. 4:447-456(2001). PubMed=11597504 [ 4] Tahirov T.H., Sato K., Ichikawa-Iwata E., Sasaki M., Inoue-Bungo T., Shiina M., Kimura K., Takata S., Fujikawa A., Morii H., Kumasaka T., Yamamoto M., Ishii S., Ogata K. "Mechanism of c-Myb-C/EBP beta cooperation from separated sites on a promoter." Cell 108:57-70(2002). PubMed=11792321 [ 5] Grotewold E., Athma P., Peterson T. "Alternatively spliced products of the maize P gene encode proteins with homology to the DNA-binding domain of myb-like transcription factors." Proc. Natl. Acad. Sci. U.S.A. 88:4587-4591(1991). PubMed=2052542 [ 6] Oppenheimer D.G., Herman P.L., Sivakumaran S., Esch J., Marks M.D. "A myb gene required for leaf trichome differentiation in Arabidopsis is expressed in stipules." Cell 67:483-493(1991). PubMed=1934056 [ 7] Marocco A., Wissenbach M., Becker D., Paz-Ares J., Saedler H., Salamini F., Rohde W. "Multiple genes are transcribed in Hordeum vulgare and Zea mays that carry the DNA binding domain of the myb oncoproteins." Mol. Gen. Genet. 216:183-187(1989). PubMed=2664447 [ 8] Tice-Baldwin K., Fink G.R., Arndt K.T. "BAS1 has a Myb motif and activates HIS4 transcription only in combination with BAS2." Science 246:931-935(1989). PubMed=2683089 [ 9] Ju Q.D., Morrow B.E., Warner J.R. "REB1, a yeast DNA-binding protein with many targets, is essential for growth and bears some resemblance to the oncogene myb." Mol. Cell. Biol. 10:5226-5234(1990). 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