Other entities represented in this entry:
HGNC Approved Gene Symbol: NEBL
Cytogenetic location: 10p12.31 Genomic coordinates (GRCh38): 10:20,779,973-21,293,050 (from NCBI)
Millevoi et al. (1998) cloned a full-length human nebulette cDNA from an adult cardiac cDNA library and found that it encodes a 109-kD protein. The predicted protein shares sequence homology with the avian nebulette protein and has 23 modular repeat structures of 35 amino acid residues each. Its domain architecture is highly related to that of the C-terminal one-third 100 kD of nebulin (161650), which is expressed only in skeletal muscle. The C-terminal regions of both nebulin and nebulette have a serine-rich domain with potential phosphorylation sites followed by an SH3 domain. RT-PCR analysis showed that nebulette was abundantly expressed in cardiac muscle, but not in skeletal or smooth muscle. Millevoi et al. (1998) also identified a nebulette splice variant that was expressed in fetal human heart. Compared with the full-length adult isoform, the deduced fetal isoform lacks nebulin repeats 16, 17, 18, and 19 and parts of nebulin repeats 15 and 20.
To identify novel disease-related genes for idiopathic dilated cardiomyopathy (CMD; see 115200), Arimura et al. (2000) constructed a normalized subtraction PCR-cDNA library between mRNAs of cardiac and skeletal muscles. One of the isolated cDNAs from this library, HS426, was expressed only in cardiac muscle. Characterization of full-length cDNAs of HS426 showed that it was identical to the nebulette cDNA cloned by Millevoi et al. (1998).
Using human zyxin (ZYX; 602002) as bait in a yeast 2-hybrid screen, Li et al. (2004) obtained a nebulette splice variant that they called LIM-nebulette. The splice variant contains 4 novel upstream exons and only exons 24, 27, and 28 of the gene structure reported by Arimura et al. (2000). The deduced 270-amino acid protein has a calculated molecular mass of 31 kD. It has an N-terminal LIM domain, 3 central nebulin-like repeats, and a C-terminal SH3 domain. Only the C-terminal SH3 domain and the last nebulin repeat are shared with full-length nebulette. Database analysis revealed a similar splice variant in mouse. Human LIM-nebulette shares 97% amino acid identity with mouse LIM-nebulette and 66% identity with human LASP1 (602920). Northern blot analysis using a LIM-nebulette-specific probe detected variable expression of an approximately 7-kb transcript in all human tissues examined. A probe that did not differentiate between nebulette and LIM-nebulette detected robust expression of 10-, 8-, and 4-kb transcripts in heart only, with weak expression of the 7-kb transcript in a range of tissues. A similar expression pattern was detected in mouse. LIM-nebulette colocalized with zyxin and LASP1 at focal adhesions in transfected HeLa and HT1080 cells.
Arimura et al. (2000) found that the nebulette gene contains 28 exons. Li et al. (2004) identified 4 additional NEBL exons 5-prime to those described by Arimura et al. (2000). Since these 4 exons are used by LIM-nebulette transcripts only, Li et al. (2004) hypothesized the presence of an upstream alternative promoter.
By radiation hybrid analysis, Millevoi et al. (1998) mapped the nebulette gene to chromosome 10p12. By FISH, Villanueva et al. (2002) mapped the nebulette gene to chromosome 10p14-p13, within the DiGeorge syndrome-2 (DGS2; 601362) deletion region.
Li et al. (2004) mapped the mouse Nebl gene to a region of chromosome 2A2 that is syntenic to human chromosome 10p12.
Millevoi et al. (1998) showed that nebulette binds to actin and plays an important role in the assembly of the Z disc.
By yeast 2-hybrid and truncation analyses, Li et al. (2004) found that the C-terminal SH3 domain of LIM-nebulette interacted with an N-terminal motif of zyxin. Protein pull-down assays confirmed direct interaction between zyxin and both full-length LIM-nebulette and its isolated SH3 domain. The zyxin motif also interacted with the C-terminal SH3 domains of LASP1 and nebulin, but not with the SH3 domains of other proteins examined.
Because the nebulette protein is a heart-specific component of the sarcomere Z disc, and because mutations in the nebulin gene are associated with nemaline myopathy of skeletal muscle (e.g., 161650.0001), Arimura et al. (2000) considered the nebulette gene as a candidate for CMD. They searched for nebulette sequence variations in Japanese patients with CMD and identified 4 sequence variations leading to amino acid replacements in the patients. These variations were also found, however, in healthy controls. Whereas the frequencies of 3 of them were similar in patients and controls, the frequency of homozygotes for asn654 to lys, a variant at a relatively conserved residue in the actin-binding motif, was significantly increased in nonfamilial CMD patients but not in familial CMD patients. The observations suggested that the asn654-to-lys polymorphism in the actin-binding motif may be a genetic marker of susceptibility to nonfamilial CMD.
Villanueva et al. (2002) determined that a genomic sequence including the NEBL gene was heterozygously deleted in cell lines derived from 2 female DGS2 patients with the proximal deletion of chromosome 10p14-p13, which is associated with cardiac and craniofacial abnormalities. One patient showed a cardiac defect, immune deficiency, cleft palate, facial dysmorphia, and developmental delay. The other showed microcephaly, microphthalmia, and hypotelorism. The NEBL gene was not deleted in cell lines derived from 2 patients with the more distal deletion of 10p14-p13, which is associated with HDR syndrome (146255).
Villanueva et al. (2002) found that expression of nebulette was decreased about 4-fold in the hearts of Hand2 (602407) null mice.
Arimura, T., Nakamura, T., Hiroi, S., Satoh, M., Takahashi, M., Ohbuchi, N., Ueda, K., Nouchi, T., Yamaguchi, N., Akai, J., Matsumori, A., Sasayama, S., Kimura, A. Characterization of the human nebulette gene: a polymorphism in an actin-binding motif is associated with nonfamilial idiopathic dilated cardiomyopathy. Hum. Genet. 107: 440-451, 2000. [PubMed: 11140941] [Full Text: https://doi.org/10.1007/s004390000389]
Li, B., Zhuang, L., Trueb, B. Zyxin interacts with the SH3 domains of the cytoskeletal proteins LIM-nebulette and Lasp-1. J. Biol. Chem. 279: 20401-20410, 2004. [PubMed: 15004028] [Full Text: https://doi.org/10.1074/jbc.M310304200]
Millevoi, S., Trombitas, K., Kolmerer, B., Kostin, S., Schaper, J., Pelin, K., Granzier, H., Labeit, S. Characterization of nebulette and nebulin and emerging concepts of their roles for vertebrate Z-discs. J. Molec. Biol. 282: 111-123, 1998. [PubMed: 9733644] [Full Text: https://doi.org/10.1006/jmbi.1998.1999]
Villanueva, M. P., Aiyer, A. R., Muller, S., Pletcher, M. T., Liu, X., Emanuel, B., Srivastava, D., Reeves, R. H. Genetic and comparative mapping of genes dysregulated in mouse hearts lacking the Hand2 transcription factor gene. Genomics 80: 593-600, 2002. [PubMed: 12504851] [Full Text: https://doi.org/10.1006/geno.2002.7009]