- Source: MYB (gene)
Myb genes are part of a large gene family of transcription factors found in animals and plants. In humans, it includes Myb proto-oncogene like 1 and Myb-related protein B in addition to MYB proper. Members of the extended SANT/Myb family also include the SANT domain and other similar all-helical homeobox-like domains.
Function
= Viral
=The Myb gene family is named after the eponymous gene in Avian myeloblastosis virus. The viral Myb (v-Myb, P01104) recognizes the sequence 5'-YAACKG-3'. It causes myeloblastosis (myeloid leukemia) in chickens. Compared to the normal animal cellular Myb (c-myb), v-myb contains deletions in the C-terminal regulatory domain, leading to aberrant activation of other oncogenes.
= Animals
=Myb proto-oncogene protein is a member of the MYB (myeloblastosis) family of transcription factors. The protein contains three domains, an N-terminal DNA-binding domain, a central transcriptional activation domain and a C-terminal domain involved in transcriptional repression. It may play a role in cell cycle regulation. Like the viral version, this gene is an oncogene, and rearrangements of the gene (often involving deletion in the C-terminal domain) causes cancer.
= Plants
=MYB factors represent a family of proteins that include the conserved MYB DNA-binding domain. Plants contain a MYB-protein subfamily that is characterised by the R2R3-type MYB domain.
In maize, phlobaphenes are synthesized in the flavonoids synthetic pathway from polymerisation of flavan-4-ols which encodes an R2R3 myb-like transcriptional activator of the A1 gene encoding for the dihydroflavonol 4-reductase (reducing dihydroflavonols into flavan-4-ols) while another gene (Suppressor of Pericarp Pigmentation 1 or SPP1) acts as a suppressor. The maize P gene encodes a Myb homolog that recognizes the sequence CCWACC, in sharp contrast with the YAACGG bound by vertebrate Myb proteins.
In sorghum, the corresponding yellow seed 1 gene (y1) also encodes a R2R3 type of Myb domain protein that regulates the expression of chalcone synthase, chalcone isomerase and dihydroflavonol reductase genes required for the biosynthesis of 3-deoxyflavonoids.
Ruby is a MYB transcriptional activator of genes that produce anthocyanin in citrus fruits. In most citrus varieties Ruby is non-functional, but in blood oranges it upregulates anthocyanin production to produce the characteristic red color of the fruit.
See also
EZH1
References
Further reading
External links
MYB+protein,+human at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Drosophila Myb oncogene-like - The Interactive Fly
Arabidospsis thaliana MYB family at Database of Arabidopsis Transcription Factors (DATF)
This article incorporates text from the United States National Library of Medicine, which is in the public domain.