Alternative titles; symbols
HGNC Approved Gene Symbol: URB1
Cytogenetic location: 21q22.11 Genomic coordinates (GRCh38) : 21:32,311,018-32,393,012 (from NCBI)
By sequencing clones obtained from a size-fractionated brain cDNA library, Nagase et al. (1998) cloned NPA1, which they designated KIAA0539. The 3-prime UTR contains Alu sequences and other repetitive elements. RT-PCR detected highest NPA1 expression in kidney, followed by liver, skeletal muscle, prostate, ovary, heart, brain, placenta, lung, testis, pancreas, and spleen. Little to no expression was detected in thymus and small intestine.
By searching for sequences similar to yeast Npa1, Dez et al. (2004) identified human NPA1, which encodes a nucleolar protein containing 2,248 amino acids.
Dez et al. (2004) found that Npa1 accumulated in the immediate vicinity of the dense fibrillar component of the nucleolus in yeast. Npa1 was predominantly associated with the 27SA2 pre-rRNA, the RNA component of the earliest pre-60S ribosomal particles. Absence of Npa1 perturbed the pre-rRNA processing pathway leading to 5.8S and 25S rRNA. Npa1 interacted with 8 putative helicases as well as with other nucleolar factors.
By radiation hybrid analysis, Nagase et al. (1998) mapped the NPA1 gene to chromosome 21.
Dez, C., Froment, C., Noaillac-Depeyre, J., Monsarrat, B., Caizergues-Ferrer, M., Henry, Y. Npa1p, a component of very early pre-60S ribosomal particles, associates with a subset of small nucleolar RNPs required for peptidyl transferase center modification. Molec. Cell. Biol. 24: 6324-6337, 2004. [PubMed: 15226434] [Full Text: https://doi.org/10.1128/MCB.24.14.6324-6337.2004]
Nagase, T., Ishikawa, K., Miyajima, N., Tanaka, A., Kotani, H., Nomura, N., Ohara, O. Prediction of the coding sequences of unidentified human genes. IX. The complete sequences of 100 new cDNA clones from brain which can code for large proteins in vitro. DNA Res. 5: 31-39, 1998. [PubMed: 9628581] [Full Text: https://doi.org/10.1093/dnares/5.1.31]