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|Coordinate||85,621,275 bp (GRCm38)|
|Base Change||C ⇒ T (forward strand)|
|Gene Name||Alstrom syndrome 1|
|Chromosomal Location||85,587,531-85,702,753 bp (+)|
|MGI Phenotype||Homozygous null mice display obesity starting after puberty, hypogonadism, hyperinsulinemia, male-specific hyperglycemia, retinal dysfunction, and late-onset hearing loss.|
|Amino Acid Change||Glutamine changed to Stop codon|
|Institutional Source||Beutler Lab|
|Gene Model||not available|
AA Change: Q1028*
|Predicted Effect||probably null|
|Phenotypic Category||adipose tissue, growth/size, increase in body weight|
|Alleles Listed at MGI|
|Mode of Inheritance||Autosomal Recessive|
|Local Stock||Live Mice, Sperm, gDNA|
|Last Updated||03/31/2017 11:04 AM by Katherine Timer|
|Record Created||01/08/2015 1:41 PM by Jeff SoRelle|
The ares phenotype was identified among N-nitroso-N-ethylurea (ENU)-mutagenized G3 mice of the pedigree R1804, some of which showed increased body weights compared to their littermates (Figure 1).
|Nature of Mutation|
Whole exome HiSeq sequencing of the G1 grandsire identified 78 mutations. The increased body weight phenotype was linked to a mutation in Alms1: a C to T transition at base pair 85,621,275 (v38) on chromosome 6, or base pair 33,779 in the GenBank genomic region NC_000072 encoding Alms1. Linkage was found with a recessive model of inheritance (P = 1.971 x 10-5), wherein 5 variant homozygotes departed phenotypically from 11 homozygous reference mice and 6 heterozygous mice (Figure 2). The mutation corresponds to residue 3,197 in the mRNA sequence NM_145223 within exon 8 of 23 total exons.
The mutated nucleotide is indicated in red, and converts glutamine 1028 of the ALMS1 protein to a stop codon.
Alms1 encodes Alström Syndrome 1 (ALMS1), which has a glutamine-rich segment (amino acids 2-80), a proline-rich segment (amino acids 90-113), a putative leucine zipper (amino acids), a large tandem repeat domain (TRD) comprised of 34 imperfect repeats of a 45-50-amino acid sequence (amino acids 440−1362), a histidine-rich region (amino acids 2582-2618), two putative nuclear localization signals, a serine-rich region, and an ALMS motif (amino acids 3124-3251) [Figure 3; (1-4)]. The functional significance of the domains of ALMS1 is unknown. Leucine zippers often function in protein-DNA or protein-protein interactions (3). The ALMS motif is also found in two other proteins, KIAA1731 and C10orf90, both of which are centriole proteins that are proposed to function in the formation and/or stability of cilia (1;2;4;5). The ares mutation results in coding of a premature stop codon after amino acid 1,028 within the TRD.
Alms1 is ubiquitously expressed (2;6). ALMS1 expression shows tissue-specific variability, with highest expression in the testis (2;3). ALMS1 localizes to centrosomes and basal bodies of cell cilia including those in human fetal pancreas, skeletal muscle, liver, kidney, hippocampus, adipocytes, within the hair cells of the developing and functionally mature cochlea, and supporting cells in the organ of Corti (4;5;7-9). During mitosis, ALMS1 localizes to the centrosomal spindle poles and during late mitosis ALMS1 localizes to the contractile ring and the cleavage furrow (10). Alms1 mRNA is upregulated in response to serum starvation (i.e., growth arrest) (11) and downregulated during adipogenesis (12). Alms1 transcription is also regulated by regulatory factor X proteins, which regulate genes of the ciliogenic pathway (13).
Cilia regulate many physiological processes including sensory (photoreception/vision, mechanosensation/hearing, and chemosensation/olfaction), embryonic development, and male fertility (14-16). Motile cilia facilitate the movement of fluids along cell surfaces as well as sperm motility, while nonmotile (primary) cilia function in the reception and transduction of extracellular signals. Primary cilia have several functions including the intraflagellar transport of signaling proteins and receptors needed for mechanosensation of lumenal flow in kidney tubules, olfaction, photoreception, and signaling through the sonic hedgehog (Shh), Wnt, and platelet-derived growth factor receptor pathways (17). Most cells have a single nonmotile primary cilium that protrudes from the apical face of the cell and is connected to the microtubule complex through the basal body. Bidirectional intraflagellar (i.e., anterograde versus retrograde) transport between the basal body and the distal tip of the cilium mediates the transport of proteins along the primary cilium. Anterograde transport is mediated by kinesin II, while retrograde transport is mediated by dynein [reviewed in (18)].
ALMS1 has putative roles in cell cycle regulation, cell migration, apoptosis, extracellular matrix production, ciliary assembly and/or function, adipogenesis, cytoplasmic microtubular organization, endosomal transport, and regulation of the transport of proteins between the cytoplasm and the ciliary axoneme (4-8;10;12;19;20). However, the precise role of ALMS1 in these processes is unknown. ALMS1 is not required for the initial development of cilia, but is required to maintain the structural and functional integrity of the cilia and/or for postnatal biogenesis of the cilium [Figure 4; (9)]. The C-terminus of ALMS1 interacts with the cytoskeletal actin-binding proteins α-actinin 1 and α-actinin 4 and other components of the endosomal recycling pathway including Huntington-associated protein isoform A (HAP1A), Rab interacting lysosomal protein-like 1 (RILPL1), myosin Vb (MYO5B; see the record new_gray for information about MYO5A), ring finger protein 31 (RNF31), RAD50 interactor 1 (RINT1), and CBP interacting protein 3 (CIP3 or EXOSC8) (10). Two of the ALMS1-interacting proteins, MYO5B and α-actinin isoform 4, are subunits of the cytoskeleton-associated recycling or transport (CART) complex, which functions in the constitutive recycling of receptors (e.g., the transferrin receptor and the β2-adrenergic receptor) from the early endosomes to the plasma membrane (21). Collin et al. propose that ALMS1 may be a component of the CART complex to mediate movement of endosomes along actin filaments to the plasma membrane (10). ALMS1 is also proposed to function in normal axonal development and migration through the regulation of neuronal intraflagellar transport. ALMS1 has a putative function in maintaining intraflagellar transport in hypothalamic-coupled neurons to regulate hypothalamic satiety and hunger (22). ALMS1 is required for the proper anchoring of C-NAP1, a regulator of centrosome organization during mitosis, at the distal end of the centriole (1). Loss of ALMS1 expression results in reduced expression levels of C-NAP1 and subsequent increased centrosome splitting, a necessary process for anaphase chromosomal division, as well as subsequent defects in cilium stability or formation (1). Short interfering RNA (siRNA)-mediated knockdown of Alms1 in mouse inner medullary collectin duct (mIMCD3) cells resulted in mislocalization of acetylated tubulin in the cells (8). However, the transcriptional program that accompanies cilia biogenesis of kidney epithelial cells was not changed upon loss of Alms1 expression (8). In addition, siRNA-mediated Alms1 knockdown in cultured neonatal mouse cardiomyocytes led to increased cell cycle progression (i.e., an increased percentage of cardiomyocytes in G2/M phases) and proliferation (19).
Homozygous or compound heterozygous mutations in ALMS1 that typically result in coding of a premature stop codon and coding of a truncated protein are linked to Alström syndrome (OMIM: #203800; (2;23)]. Alström syndrome has variable symptoms including childhood obesity due to an excess accumulation of subcutaneous adipose tissue, hyperinsulinemia, acanthosis nigricans (a marker of severe insulin resistance), type 2 diabetes mellitus, hypertriglyceridemia that can lead to acute pancreatitis, hypothyroidsism, growth hormone deficiency, sensorineural hearing loss, and progressive rod-cone dystrophy leading to blindness [(24); reviewed in (25;26)]. Approximately 70% of patients with Alström syndrome also have dilated cardiomyopathy during infancy or adolescence [(19); reviewed in (25)]. In addition, many patients have hepatic and urologic dysfunction as well as renal failure and systemic fibrosis with age [reviewed in (25)]. Patients exhibit hypogonadotropic hypogonadism leading to infertility and female patients have symptoms of polycystic ovary syndrome and hyperandrogenism (25;27). The symptoms of Alström syndrome lead to high morbidity and reduced life expectancy (25).
Several Alms1 mutant mouse models (fat aussie (foz), Alms1L2131X, and Alms1-/-) have been characterized. The foz phenotype was linked to a spontaneous 11-base pair (bp 3918-3928) deletion within exon 8 of Alms1 resulting in a frame-shift and coding of a premature stop codon (28). The ENU-induced Alms1 mutation, Alms1L2131X, resulted in premature truncation of the protein at amino acid 2,130 (8). The Alms1-/- model is a gene-trapped Alms1 allele (6;29). All of the mouse models exhibited rapid weight gain due to an increase in body fat and increased eating at weaning so that by 8 weeks of age they were significantly heavier than wild-type mice (6;8;9;29;30). All of the mutant Alms1 alleles also resulted in hyperinsulinemia, increased cholesterol levels (total and HDL), moderate late-onset (after ~16 weeks) diabetes only in the male mice, steatosis of the liver, hyperplastic pancreatic islets, and hypogonadism leading to infertility in the male mice (6;8;28-30). The Alms1-/- retina exhibited age-related degeneration and defective transport of rhodopsin (see the record for Bemr3), the major protein in rod photoreceptor outer segment discs; membrane-bound vesicles accumulated in the distal portion of the inner segments near the connecting cilium (8). Alms1 mutations also led to age-related cochlear degeneration and hearing loss. The Alms1-/- mice exhibited misshapen stereociliary outer hair bundles and mislocalized kinocilia; the inner hair cells bundles in the Alms1-/- mice were largely normal (5). Young female foz/foz mice were fertile, but litter sizes were smaller than those of wild-type or heterozygous mice (28). After the female mice became obese, they became infertile and the ovaries were devoid of corpora lutea, indicating an anovulatory state (28). The foz/foz mice also exhibited a reduction in neurons that displayed cilia marked with adenylyl cyclase 3, a signaling protein that regulates obesity, as well as a reduction in cilia that contained the appetite-regulating proteins, Mchr1 and Sstr3 (9). When fed a high-fat diet the foz/foz mice undergo transition of steatosis to severe fibrosing steatohepatitis that includes the majority of hepatocytes exhibiting severe ballooning degeneration, lobular inflammation, and pericellular and pericentral fibrosis (30). The transition after high-fat diet was associated with higher hepatic triglyceride levels compared to chow-fed foz/foz mice (30). Total GLUT4 content, insulin-stimulated GLUT4 translocation, and glucose uptake was reduced in the Alms1-/- mice indicating that ALMS1 mediates glucose homeostasis through the GLUT4 trafficking pathway (29). The Alms1-/- mice could respond to insulin by stimulating AKT phosphorylation indicating that the impaired GLUT4 translocation is downstream of AKT activation or is independent of AKT signaling.
Centrosome and basal body dysfunction as a result of mutations in Alms1 are predicted to lead to the pathogenesis of obesity, insulin resistance, and type 2 diabetes. Although the exact function of ALMS1 is unknown, it has been shown to be essential in weight regulation. Other ALMS1-related phenotypes have not been tested or observed in ares, but the weight gain phenotype indicates that the mutation results in loss-of-function.
ares(F):5'- AGCAGCCTATGTCAGATAGTCAG -3'
ares(R):5'- AGAGCCAGAGCCTACTGATTTC -3'
ares_seq(F):5'- GCCTATGTCAGATAGTCAGCGAAC -3'
ares_seq(R):5'- CCAGAGCCTACTGATTTCAAAAATAC -3'
1. Knorz, V. J., Spalluto, C., Lessard, M., Purvis, T. L., Adigun, F. F., Collin, G. B., Hanley, N. A., Wilson, D. I., and Hearn, T. (2010) Centriolar Association of ALMS1 and Likely Centrosomal Functions of the ALMS Motif-Containing Proteins C10orf90 and KIAA1731. Mol Biol Cell. 21, 3617-3629.
2. Collin, G. B., Marshall, J. D., Ikeda, A., So, W. V., Russell-Eggitt, I., Maffei, P., Beck, S., Boerkoel, C. F., Sicolo, N., Martin, M., Nishina, P. M., and Naggert, J. K. (2002) Mutations in ALMS1 Cause Obesity, Type 2 Diabetes and Neurosensory Degeneration in Alstrom Syndrome. Nat Genet. 31, 74-78.
3. Hearn, T., Renforth, G. L., Spalluto, C., Hanley, N. A., Piper, K., Brickwood, S., White, C., Connolly, V., Taylor, J. F., Russell-Eggitt, I., Bonneau, D., Walker, M., and Wilson, D. I. (2002) Mutation of ALMS1, a Large Gene with a Tandem Repeat Encoding 47 Amino Acids, Causes Alstrom Syndrome. Nat Genet. 31, 79-83.
4. Hearn, T., Spalluto, C., Phillips, V. J., Renforth, G. L., Copin, N., Hanley, N. A., and Wilson, D. I. (2005) Subcellular Localization of ALMS1 Supports Involvement of Centrosome and Basal Body Dysfunction in the Pathogenesis of Obesity, Insulin Resistance, and Type 2 Diabetes. Diabetes. 54, 1581-1587.
5. Jagger, D., Collin, G., Kelly, J., Towers, E., Nevill, G., Longo-Guess, C., Benson, J., Halsey, K., Dolan, D., Marshall, J., Naggert, J., and Forge, A. (2011) Alstrom Syndrome Protein ALMS1 Localizes to Basal Bodies of Cochlear Hair Cells and Regulates Cilium-Dependent Planar Cell Polarity. Hum Mol Genet. 20, 466-481.
6. Collin, G. B., Cyr, E., Bronson, R., Marshall, J. D., Gifford, E. J., Hicks, W., Murray, S. A., Zheng, Q. Y., Smith, R. S., Nishina, P. M., and Naggert, J. K. (2005) Alms1-Disrupted Mice Recapitulate Human Alstrom Syndrome. Hum Mol Genet. 14, 2323-2333.
7. Andersen, J. S., Wilkinson, C. J., Mayor, T., Mortensen, P., Nigg, E. A., and Mann, M. (2003) Proteomic Characterization of the Human Centrosome by Protein Correlation Profiling. Nature. 426, 570-574.
8. Li, G., Vega, R., Nelms, K., Gekakis, N., Goodnow, C., McNamara, P., Wu, H., Hong, N. A., and Glynne, R. (2007) A Role for Alstrom Syndrome Protein, alms1, in Kidney Ciliogenesis and Cellular Quiescence. PLoS Genet. 3, e8.
9. Heydet, D., Chen, L. X., Larter, C. Z., Inglis, C., Silverman, M. A., Farrell, G. C., and Leroux, M. R. (2013) A Truncating Mutation of Alms1 Reduces the Number of Hypothalamic Neuronal Cilia in Obese Mice. Dev Neurobiol. 73, 1-13.
10. Collin, G. B., Marshall, J. D., King, B. L., Milan, G., Maffei, P., Jagger, D. J., and Naggert, J. K. (2012) The Alstrom Syndrome Protein, ALMS1, Interacts with Alpha-Actinin and Components of the Endosome Recycling Pathway. PLoS One. 7, e37925.
11. Yabuta, N., Onda, H., Watanabe, M., Yoshioka, N., Nagamori, I., Funatsu, T., Toji, S., Tamai, K., and Nojima, H. (2006) Isolation and Characterization of the TIGA Genes, Whose Transcripts are Induced by Growth Arrest. Nucleic Acids Res. 34, 4878-4892.
12. Romano, S., Milan, G., Veronese, C., Collin, G. B., Marshall, J. D., Centobene, C., Favaretto, F., Dal Pra, C., Scarda, A., Leandri, S., Naggert, J. K., Maffei, P., and Vettor, R. (2008) Regulation of Alstrom Syndrome Gene Expression during Adipogenesis and its Relationship with Fat Cell Insulin Sensitivity. Int J Mol Med. 21, 731-736.
13. Purvis, T. L., Hearn, T., Spalluto, C., Knorz, V. J., Hanley, K. P., Sanchez-Elsner, T., Hanley, N. A., and Wilson, D. I. (2010) Transcriptional Regulation of the Alstrom Syndrome Gene ALMS1 by Members of the RFX Family and Sp1. Gene. 460, 20-29.
14. Berbari, N. F., O'Connor, A. K., Haycraft, C. J., and Yoder, B. K. (2009) The Primary Cilium as a Complex Signaling Center. Curr Biol. 19, R526-35.
15. Gerdes, J. M., Davis, E. E., and Katsanis, N. (2009) The Vertebrate Primary Cilium in Development, Homeostasis, and Disease. Cell. 137, 32-45.
16. Goetz, S. C., and Anderson, K. V. (2010) The Primary Cilium: A Signalling Centre during Vertebrate Development. Nat Rev Genet. 11, 331-344.
17. Singla, V., and Reiter, J. F. (2006) The Primary Cilium as the Cell's Antenna: Signaling at a Sensory Organelle. Science. 313, 629-633.
18. Rosenbaum, J. L., and Witman, G. B. (2002) Intraflagellar Transport. Nat Rev Mol Cell Biol. 3, 813-825.
19. Shenje, L. T., Andersen, P., Halushka, M. K., Lui, C., Fernandez, L., Collin, G. B., Amat-Alarcon, N., Meschino, W., Cutz, E., Chang, K., Yonescu, R., Batista, D. A., Chen, Y., Chelko, S., Crosson, J. E., Scheel, J., Vricella, L., Craig, B. D., Marosy, B. A., Mohr, D. W., Hetrick, K. N., Romm, J. M., Scott, A. F., Valle, D., Naggert, J. K., Kwon, C., Doheny, K. F., and Judge, D. P. (2014) Mutations in Alstrom Protein Impair Terminal Differentiation of Cardiomyocytes. Nat Commun. 5, 3416.
20. Zulato, E., Favaretto, F., Veronese, C., Campanaro, S., Marshall, J. D., Romano, S., Cabrelle, A., Collin, G. B., Zavan, B., Belloni, A. S., Rampazzo, E., Naggert, J. K., Abatangelo, G., Sicolo, N., Maffei, P., Milan, G., and Vettor, R. (2011) ALMS1-Deficient Fibroblasts Over-Express Extra-Cellular Matrix Components, Display Cell Cycle Delay and are Resistant to Apoptosis. PLoS One. 6, e19081.
21. Yan, Q., Sun, W., Kujala, P., Lotfi, Y., Vida, T. A., and Bean, A. J. (2005) CART: An Hrs/actinin-4/BERP/myosin V Protein Complex Required for Efficient Receptor Recycling. Mol Biol Cell. 16, 2470-2482.
22. Mok, C. A., Heon, E., and Zhen, M. (2010) Ciliary Dysfunction and Obesity. Clin Genet. 77, 18-27.
23. Joy, T., Cao, H., Black, G., Malik, R., Charlton-Menys, V., Hegele, R. A., and Durrington, P. N. (2007) Alstrom Syndrome (OMIM 203800): A Case Report and Literature Review. Orphanet J Rare Dis. 2, 49.
24. Marshall, J. D., Bronson, R. T., Collin, G. B., Nordstrom, A. D., Maffei, P., Paisey, R. B., Carey, C., Macdermott, S., Russell-Eggitt, I., Shea, S. E., Davis, J., Beck, S., Shatirishvili, G., Mihai, C. M., Hoeltzenbein, M., Pozzan, G. B., Hopkinson, I., Sicolo, N., Naggert, J. K., and Nishina, P. M. (2005) New Alstrom Syndrome Phenotypes Based on the Evaluation of 182 Cases. Arch Intern Med. 165, 675-683.
25. Marshall, J. D., Beck, S., Maffei, P., and Naggert, J. K. (2007) Alstrom Syndrome. Eur J Hum Genet. 15, 1193-1202.
26. Girard, D., and Petrovsky, N. (2011) Alstrom Syndrome: Insights into the Pathogenesis of Metabolic Disorders. Nat Rev Endocrinol. 7, 77-88.
27. Dunaif, A. (1997) Insulin Resistance and the Polycystic Ovary Syndrome: Mechanism and Implications for Pathogenesis. Endocr Rev. 18, 774-800.
28. Arsov, T., Silva, D. G., O'Bryan, M. K., Sainsbury, A., Lee, N. J., Kennedy, C., Manji, S. S., Nelms, K., Liu, C., Vinuesa, C. G., de Kretser, D. M., Goodnow, C. C., and Petrovsky, N. (2006) Fat Aussie--a New Alstrom Syndrome Mouse Showing a Critical Role for ALMS1 in Obesity, Diabetes, and Spermatogenesis. Mol Endocrinol. 20, 1610-1622.
29. Favaretto, F., Milan, G., Collin, G. B., Marshall, J. D., Stasi, F., Maffei, P., Vettor, R., and Naggert, J. K. (2014) GLUT4 Defects in Adipose Tissue are Early Signs of Metabolic Alterations in Alms1GT/GT, a Mouse Model for Obesity and Insulin Resistance. PLoS One. 9, e109540.
|Science Writers||Anne Murray|
|Authors||Zhe Chen, Jeff SoRelle, Noelle Hutchins|
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