BUD23

This gene encodes a protein containing a nuclear localization signal and an S-adenosyl-L-methionine binding motif typical of methyltransferases, suggesting that the encoded protein may act on DNA methylation. This gene is deleted in Williams syndrome, a multisystem developmental disorder caused by the deletion of contiguous genes at 7q11.23. Alternatively spliced transcript variants have been found.

Full Name

BUD23, rRNA methyltransferase and ribosome maturation factor

Function

S-adenosyl-L-methionine-dependent methyltransferase that specifically methylates the N7 position of a guanine in 18S rRNA (PubMed:25851604).
Requires the methyltransferase adapter protein TRM112 for full rRNA methyltransferase activity (PubMed:25851604).
Involved in the pre-rRNA processing steps leading to small-subunit rRNA production independently of its RNA-modifying catalytic activity (PubMed:25851604).
Important for biogenesis end export of the 40S ribosomal subunit independent on its methyltransferase activity (PubMed:24086612).
Locus-specific steroid receptor coactivator. Potentiates transactivation by glucocorticoid (NR3C1), mineralocorticoid (NR3C2), androgen (AR) and progesterone (PGR) receptors (PubMed:24488492).
Required for the maintenance of open chromatin at the TSC22D3/GILZ locus to facilitate NR3C1 loading on the response elements (PubMed:24488492).
Required for maintenance of dimethylation on histone H3 'Lys-79' (H3K79me2), although direct histone methyltransferase activity is not observed in vitro (PubMed:24488492).

Biological Process

Chromatin organization Source: UniProtKB-KW
Positive regulation of rRNA processing Source: UniProtKB
rRNA (guanine-N7)-methylation Source: UniProtKB
rRNA methylation Source: Reactome

Cellular Location

Cytoplasm; Nucleus; Nucleoplasm; Perinuclear region. Localized diffusely throughout the nucleus and the cytoplasm (PubMed:24488492). Localizes to a polarized perinuclear structure, overlapping partially with the Golgi and lysosomes (PubMed:25851604). Localization is not affected by glucocorticoid treatment (PubMed:24488492).

Involvement in disease

BUD23 is located in the Williams-Beuren syndrome (WBS) critical region. WBS results from a hemizygous deletion of several genes on chromosome 7q11.23, thought to arise as a consequence of unequal crossing over between highly homologous low-copy repeat sequences flanking the deleted region. Haploinsufficiency of BUD23 may be the cause of certain cardiovascular and musculo-skeletal abnormalities observed in the disease.

PTM

May be ubiquitinated and targeted to degradation in response to proinflammatory cytokine signaling.