Alternative titles; symbols
HGNC Approved Gene Symbol: NIN
Cytogenetic location: 14q22.1 Genomic coordinates (GRCh38) : 14:50,719,763-50,831,503 (from NCBI)
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
|---|---|---|---|---|
| 14q22.1 | ?Seckel syndrome 7 | 614851 | Autosomal recessive | 3 |
Ninein is a centrosomal protein required for the centrosome to function as a microtubule-organizing center (MTOC) and is essential for the reformation of the interphase centrosome architecture following mitosis (Ou et al., 2002).
By sequencing clones obtained from a size-fractionated fetal brain cDNA library, Nagase et al. (2000) cloned NIN, which they designated KIAA1565. RT-PCR ELISA detected high NIN expression in ovary, spleen, adult whole brain, and all individual brain regions examined. Expression was intermediate in all other adult and fetal tissues examined except testis, which showed no expression.
Using GSK3B (605004) as bait in a yeast 2-hybrid screen of a fetal liver cDNA library, followed by EST contig searching and 5-prime RACE of fetal liver cDNA, Hong et al. (2000) cloned full-length NIN. The deduced 2,047-amino acid protein has a calculated molecular mass of 239 kD. NIN contains an N-terminal GTP-binding site, a large coiled-coil domain with 4 leucine zipper motifs, and a C-terminal domain responsible for GSK binding. Unlike mouse Nin, it does not have an N-terminal Ca(2+)-binding site. Northern blot analysis detected a 9.0-kb transcript in all tissues examined and a 7.0-kb transcript predominantly in heart and skeletal muscle. Fluorescence-labeled NIN localized in the perinuclear foci characteristic of centrosomes in transfected COS-1 cells.
Hong et al. (2000) cloned a splice variant of NIN, which they designated ninein-lm (ninein like mouse) because the protein contains an N-terminal Ca(2+)-binding site. This variant lacks intron 1 and utilizes an alternate splice site in exon 2 that results in more 5-prime sequence of exon 2. Ninein-lm encodes a deduced 2,041-amino acid protein with a calculated molecular mass of 238 kD. RT-PCR and Southern blot analysis indicated that ninein-lm expression was 20- to 50-fold higher than ninein expression in all tissues tested except pancreas.
By Western blot analysis, Chen et al. (2003) determined that endogenous HeLa cell ninein had an apparent molecular mass of about 230 kD.
By RT-PCR of mouse RNA extracted from various tissues of newborn mice, Grosch et al. (2013) observed expression of NIN in all tissues analyzed, including cartilage, bone, and brain.
Hong et al. (2000) determined that the NIN gene contains 29 exons and spans about 130 kb. The promoter region contains a TATA box, 2 CCAAT boxes, and 3 GC boxes. It also has 4 Sp1 (189906)-binding sites, 2 p300 (602700)-binding sites, and 1 AP1 (165160)-binding site.
By genomic sequence analysis and radiation hybrid analysis, Hong et al. (2000) mapped the NIN gene to chromosome 14q22.
Hong et al. (2000) determined that the C termini of ninein and ninein-lm bound GSK3B. The coiled-coil domain, but not the leucine-zipper domains, mediated the interaction. The coiled-coil domain also mediated oligomerization.
The mammalian centrosome consists of a pair of centrioles surrounded by pericentriolar material (PCM). Ou et al. (2002) stated that a subset of PCM proteins are arranged in a tubular conformation with an open and a closed end within the centrosome. They found that, in the mother centrosome, ninein and CEP110 (605496) were distributed at both ends of the centrosome tube, including the site of centrosome duplication. However, in the daughter centrosome, ninein and CEP110 were present only at the closed end, where they colocalized with CEP250. The appearance of ninein and CEP110 at the open end of the daughter centrosome occurred during the telophase-G1 transition of the next cell cycle, concomitant with the maturation of the daughter centrosome into a mother centrosome. Microinjection of antibodies against either ninein or CEP110 into metaphase HeLa cells disrupted the reformation of the tubular conformation of proteins within the centrosome following cell division and led to dispersal of centrosomal material throughout the cytosol. Microinjection of antibodies to either ninein or CEP110 into metaphase kangaroo rat kidney cells not only disrupted the tubular configuration within the centrosome, but also affected the centrosome's ability to function as an MTOC. Centrosomal architecture was not disrupted if antibodies were microinjected into postmitotic cells with fully formed centrosomes, but the MTOC function of the centrosomes was disrupted.
Chen et al. (2003) showed that the coiled-coil II (CCII) domain of ninein, which contains a centrosome targeting signal, colocalized with gamma-tubulin (191135) and centrin (see CENT1 603187) at the centrosome of transfected HeLa cells. Immunofluorescence microscopy showed that ninein protein disappeared from spindle poles during metaphase and anaphase, but reaccumulated at centrosomes at the end of cell division. In vitro kinase assays indicated that the CCII domain was readily phosphorylated by AIK (AURKA; 603072) and PKA (see 176911).
By yeast 2-hybrid and in vitro binding analyses, Lieu et al. (2010) showed that both isoforms of human AIBP (AUNIP; 620397) bound Aurora A (AURKA). The interaction was mediated by the C terminus of AIBP and required kinase activity and the D-box domain of Aurora A. The authors found that the N-terminal region of AIBP bound ninein, and Aurora A and ninein colocalized with AIBP in transfected HeLa cells. Yeast 3-hybrid analysis revealed that AIBP interacted with Aurora A and ninein simultaneously and functioned as a bridging protein. An in vitro kinase assay showed that AIBP was a substrate for Aurora A. AIBP interaction with Aurora A functioned as a positive regulator of Aurora A phosphorylation of histone H3 (see 602810) and MBP (159430). AIBP interaction with ninein blocked phosphorylation of ninein by both Aurora A and GSK3B. Knockdown analysis in HeLa cells revealed that AIBP was required for localization of Aurora A to spindle poles and spindle.
Using a yeast 2-hybrid screen, Chou et al. (2015) showed that AIBP bound PLK1 (602098) via its C-terminal region, thereby anchoring Aurora A, ninein, and PLK1 to form a complex. Immunofluorescence assays revealed that AIBP colocalized with Aurora A and PLK1 on centrosome and spindle poles during early mitosis and metaphase in HeLa cells. In vitro kinase assays demonstrated that PLK1 phosphorylated AIBP at its N terminus. In turn, AIBP acted as a positive regulator for both PLK1 and Aurora A in their phosphorylation of histone H3 and MBP. Moreover, similar to Aurora A, PLK1 phosphorylated ninein, and this phosphorylation was blocked by AIBP. AIBP activated Aurora A, and activated Aurora A enhanced PLK1 activity by phosphorylating PLK1 at thr210. Thus, AIBP appeared to play a dual role in regulating PLK1, as it directly activated Aurora A to phosphorylate PLK1, and it bound PLK1 to enhance conformational accessibility for Aurora A. In the complex, ninein was involved in recruiting AIBP to centrosomes, as ninein knockdown blocked centrosomal targeting of AIBP in HeLa cells. However, AIBP was not involved in microtubule nucleation during interphase, as depletion of AIBP did not affect localization of ninein and microtubule nucleation in HeLa cells. AIBP depletion in HeLa cells confirmed that AIBP affected the activities of both Aurora A and PLK1, as phosphorylation of PLK1 at thr210 and of Aurora A at thr288 was decreased. AIBP also functioned during mitosis, as knockdown of AIBP in mitotic HeLa cells resulted in asymmetrical spindle poles, multipolar spindles, donut-shaped chromosomes, and chromosome misalignment. AIBP was involved in regulation of the Aurora A/TACC3 (605303)/CHTOG (CKAP5; 611142) complex that maintains centrosome structure, as loss of AIBP dominantly caused mislocalization of the Aurora A downstream proteins TACC3 and CHTOG.
Seckel Syndrome 7
In 2 sisters with severe short stature, microcephaly, and developmental delay (Seckel syndrome-7; SCKL7, 614851), Dauber et al. (2012) identified compound heterozygosity for missense mutations in the NIN gene (Q1222R, 608684.0001; N1709S, 608684.0002).
Associations Pending Confirmation
For discussion of a possible association between mutation in the NIN gene and a form of the leptodactylic type of spondyloepimetaphyseal dysplasia with joint laxity, see 608684.0003.
Dauber et al. (2012) performed morpholino knockdown of ninein in zebrafish and observed defects in the anterior neuroectoderm that resulted in a deformity of the developing cranium, with a small, squared skull highly reminiscent of the human phenotype.
In 2 sisters with severe short stature, microcephaly, and developmental delay (SCKL7; 614851), Dauber et al. (2012) identified compound heterozygosity for a 3667G-A transition in exon 18 of the NIN gene, resulting in a gln1222-to-arg (Q1222R) substitution, and a 5128A-G transition in exon 23, resulting in an asn1709-to-ser (N1709S; 608684.0002) substitution; both substitutions occurred at evolutionarily conserved residues. The unaffected parents were each heterozygous for 1 of the mutations, neither of which was present in the SNP or the NHLBI Exome Variant Server databases; however, the Q1222R variant was present in the 1000 Genomes Project pilot data, with an overall minor allele frequency of 0.001. Functional analysis of patient fibroblasts suggested that the compound heterozygous NIN defects did not disrupt ninein expression or localization or affect mitotic functions in an obvious way.
For discussion of the asn1709-to-ser (N1709S) mutation in the NIN gene that was found in compound heterozygous state in sisters with severe short stature, microcephaly, and developmental delay (SCKL7; 614851) by Dauber et al. (2012), see 608684.0001.
This variant is classified as a variant of unknown significance because its contribution to a leptodactylic form of spondyloepimetaphyseal dysplasia with joint laxity (see, e.g., SEMDJL, 603546) has not been confirmed.
In 4 affected members of a consanguineous Turkish family with a leptodactylic form of spondyloepimetaphyseal dysplasia with joint laxity, Grosch et al. (2013) identified homozygosity for a c.6435A-G transition (c.6435A-G, NM_020921) in exon 31 of the NIN gene, resulting in an asn2082-to-asp (N2082D) substitution at a highly conserved residue located at a helix position within the most C-terminal of 11 coiled-coil regions. The 4 affected individuals were also homozygous for a P95S mutation in the POLE2 gene (602670). Both mutations segregated fully with disease in the family, and neither was found in 200 Turkish or 300 German controls. Clinical details were available only from the proband, a 35-year-old woman who was born with bilateral hip dysplasia and had markedly delayed early motor development, with painful hip and knee joints as well as generalized laxity of her small and large joints. Examination at age 35 showed disproportionate short stature and microcephaly, flat face with short nose and flat nasal bridge, and moderate retrognathia. She had a narrow, high palate and her teeth were carious. In addition to short arms and legs and laxity of most joints, she exhibited genua valga and bilateral pes cavus deformity. Radiologic examination showed squared vertebral bodies with irregular endplates, bilateral hip dysplasia and dislocation as well as epiphyseal dysplasia and metaphyseal changes of long tubular bones including poor modeling and fine vertical striations at the metaphyses of distal femur and proximal tibia. In contrast, hand radiographs showed strikingly slender (leptodactylic) metacarpals and phalanges. The proband had an affected sister with short stature who was reported to have scoliosis and joint pain, and 2 female cousins who were also reported to have short stature and a similar phenotype. All 4 were of normal intelligence. The other 3 affected individuals declined clinical investigation, and none of the 4 gave permission to publish photographs.
Because the mutation in the POLE2 gene occurred in a sequence stretch with a low level of regular secondary structure, with only poor sequence conservation, Grosch et al. (2013) concluded that it was unlikely to have a pronounced effect on the structure or function of POLE2. In contrast, the N2082D mutation in NIN was predicted to create an electrostatic repulsion with glu2081 on the second subunit, and thus to weaken or entirely disrupt the coiled coil. The authors noted that exon 31 is exclusively present in isoform 2, and suggested that this might account for the milder phenotype in this family compared to that in the sisters with Seckel syndrome studied by Dauber et al. (2012) (see 608684.0001), in whom the mutations affected all 4 NIN splice variants.
Chen, C.-H., Howng, S.-L., Cheng, T.-S., Chou, M.-H., Huang, C.-Y., Hong, Y.-R. Molecular characterization of human ninein protein: two distinct subdomains required for centrosomal targeting and regulating signals in cell cycle. Biochem. Biophys. Res. Commun. 308: 975-983, 2003. [PubMed: 12927815] [Full Text: https://doi.org/10.1016/s0006-291x(03)01510-9]
Chou, C. H., Loh, J. K., Yang, M. C., Lin, C. C., Hong, M. C., Cho, C. L., Chou, A. K., Wang, C. H., Lieu, A. S., Howng, S. L., Hsu, C. M., Hong, Y. R. AIBp regulates mitotic entry and mitotic spindle assembly by controlling activation of both Aurora-A and Plk1. Cell Cycle 14: 2764-2776, 2015. [PubMed: 26114227] [Full Text: https://doi.org/10.1080/15384101.2015.1066536]
Dauber, A., LaFranchi, S. H., Maliga, Z., Lui, J. C., Moon, J. E., McDeed, C., Henke, K., Zonana, J., Kingman, G. A., Pers, T. H., Baron, J., Rosenfeld, R. G., Hirschhorn, J. N., Harris, M. P., Hwa, V. Novel microcephalic primordial dwarfism disorder associated with variants in the centrosomal protein ninein. J. Clin. Endocr. Metab. 97: E2140-E2151, 2012. Note: Electronic Article. [PubMed: 22933543] [Full Text: https://doi.org/10.1210/jc.2012-2150]
Grosch, M., Gruner, B., Spranger, S., Stutz, A. M., Rausch, T., Korbel, J. O., Seelow, D., Nurnberg, P., Stricht, H., Lausch, E., Zabel, B., Winterpacht, A., Tagariello, A. Identification of a ninein (NIN) mutation in a family with spondyloepimetaphyseal dysplasia with joint laxity (leptodactylic type)-like phenotype. Matrix Biol. 32: 387-392, 2013. [PubMed: 23665482] [Full Text: https://doi.org/10.1016/j.matbio.2013.05.001]
Hong, Y.-R., Chen, C.-H., Chang, J.-H., Wang, S., Sy, W.-D., Chou, C.-K., Howng, S.-L. Cloning and characterization of a novel human Ninein protein that interacts with the glycogen synthase kinase 3-beta. Biochim. Biophys. Acta 1492: 513-516, 2000. [PubMed: 11004522] [Full Text: https://doi.org/10.1016/s0167-4781(00)00127-5]
Hong, Y.-R., Chen, C.-H., Chuo, M.-H., Liou, S.-Y., Howng, S.-L. Genomic organization and molecular characterization of the human Ninein gene. Biochem. Biophys. Res. Commun. 279: 989-995, 2000. [PubMed: 11162463] [Full Text: https://doi.org/10.1006/bbrc.2000.4050]
Lieu, A. S., Cheng, T. S., Chou, C. H., Wu, C. H., Hsu, C. Y., Huang, C. Y., Chang, L. K., Loh, J. K., Chang, C. S., Hsu, C. M., Howng, S. L., Hong, Y. R. Functional characterization of AIBp, a novel Aurora-A binding protein in centrosome structure and spindle formation. Int. J. Oncol. 37: 429-436, 2010. [PubMed: 20596670] [Full Text: https://doi.org/10.3892/ijo_00000691]
Nagase, T., Kikuno, R., Nakayama, M., Hirosawa, M., Ohara, O. Prediction of the coding sequences of unidentified human genes. XVIII. The complete sequences of 100 new cDNA clones from brain which code for large proteins in vitro. DNA Res. 7: 273-281, 2000. [PubMed: 10997877] [Full Text: https://doi.org/10.1093/dnares/7.4.271]
Ou, Y. Y., Mack, G. J., Zhang, M., Rattner, J. B. CEP110 and ninein are located in a specific domain of the centrosome associated with centrosome maturation. J. Cell Sci. 115: 1825-1835, 2002. [PubMed: 11956314] [Full Text: https://doi.org/10.1242/jcs.115.9.1825]