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Petazzi P, Miquel‐Serra L, Huertas S, González C, Boto N, Muñiz‐Diaz E, Menéndez P, Sevilla A, Nogués N. ABO gene editing for the conversion of blood type A to universal type O in Rh null donor-derived human-induced pluripotent stem cells. Clin Transl Med 2022; 12:e1063. [PMID: 36281739 PMCID: PMC9593258 DOI: 10.1002/ctm2.1063] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/13/2022] [Accepted: 09/06/2022] [Indexed: 01/28/2023] Open
Abstract
The limited availability of red cells with extremely rare blood group phenotypes is one of the global challenges in transfusion medicine that has prompted the search for alternative self-renewable pluripotent cell sources for the in vitro generation of red cells with rare blood group types. One such phenotype is the Rhnull , which lacks all the Rh antigens on the red cell membrane and represents one of the rarest blood types in the world with only a few active blood donors available worldwide. Rhnull red cells are critical for the transfusion of immunized patients carrying the same phenotype, besides its utility in the diagnosis of Rh alloimmunization when a high-prevalence Rh specificity is suspected in a patient or a pregnant woman. In both scenarios, the potential use of human-induced pluripotent stem cell (hiPSC)-derived Rhnull red cells is also dependent on ABO compatibility. Here, we present a CRISPR/Cas9-mediated ABO gene edition strategy for the conversion of blood type A to universal type O, which we have applied to an Rhnull donor-derived hiPSC line, originally carrying blood group A. This work provides a paradigmatic example of an approach potentially applicable to other hiPSC lines derived from rare blood donors not carrying blood type O.
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Affiliation(s)
- Paolo Petazzi
- Josep Carreras Leukemia Research InstituteBarcelonaSpain
| | - Laia Miquel‐Serra
- Immunohematology LaboratoryBarcelonaSpain
- Transfusional medicine. Vall d'Hebron Research Institute (VHIR)BarcelonaSpain
| | - Sergio Huertas
- Immunohematology LaboratoryBarcelonaSpain
- Transfusional medicine. Vall d'Hebron Research Institute (VHIR)BarcelonaSpain
| | - Cecilia González
- Immunohematology LaboratoryBarcelonaSpain
- Transfusional medicine. Vall d'Hebron Research Institute (VHIR)BarcelonaSpain
| | - Neus Boto
- Immunohematology LaboratoryBarcelonaSpain
| | - Eduardo Muñiz‐Diaz
- Immunohematology LaboratoryBarcelonaSpain
- Transfusional medicine. Vall d'Hebron Research Institute (VHIR)BarcelonaSpain
- Department of MedicineUniversitat Autònoma de Barcelona (UAB)BarcelonaSpain
| | - Pablo Menéndez
- Josep Carreras Leukemia Research InstituteBarcelonaSpain
- Department of Biomedicine, School of MedicineUniversity of BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red de Cáncer‐CIBER‐ONCInstituto de Salud Carlos IIIBarcelonaSpain
- Red Española de Terapias Avanzadas (TERAV)Instituto de Salud Carlos III (RICORS, RD21/0017/0029)
- Institució Catalana de Recerca i Estudis Avançats (ICREA)BarcelonaSpain
| | - Ana Sevilla
- Department of Cell BiologyPhysiology and Immunology, Faculty of Biology, University of BarcelonaBarcelonaSpain
- Institute of Biomedicine of the University of Barcelona (IBUB)BarcelonaSpain
| | - Núria Nogués
- Immunohematology LaboratoryBarcelonaSpain
- Transfusional medicine. Vall d'Hebron Research Institute (VHIR)BarcelonaSpain
- Department of MedicineUniversitat Autònoma de Barcelona (UAB)BarcelonaSpain
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Xia RW, Xun CZ, Xiang D, Zhang JM, Yang QX, Zhao FY, Wang C, Zhu ZY, Li Q, Ye LY. A novel double-variant RHAG allele leads to Rh mod phenotype. Transfus Med 2019; 29:460-465. [PMID: 31032541 DOI: 10.1111/tme.12598] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 01/30/2019] [Accepted: 04/02/2019] [Indexed: 12/28/2022]
Abstract
AIMS/OBJECTIVES We aimed to analyse the molecular backgrounds and red blood cell (RBC) antigen expression of a male blood donor with Rhmod phenotype and his family members. BACKGROUND Rh deficiency phenotypes are rarely found worldwide and are characterised by the lack of Rh antigen expression on RBCs. During routine screening, we found a blood donor who seemingly lacked Rh antigens. Therefore, we recruited the donor and his family for further investigation. METHODS RBC serotyping and antibody screening/identification were performed for each sample. A routine blood examination was also conducted. RHD, RHCE and RHAG were sequenced at the genomic DNA or RNA level. Eleven antigens or proteins associated with Rh complex were tested using flow cytometry analysis. RESULTS The proband and one of his brothers showed extremely weak D antigen and Rh expression levels but did not manifest anaemia. Most of the expressed RBC antigens of the two Rh-deficient individuals were similar to the previously reported cases but with some exceptions. Molecular analyses demonstrated homozygous expression of a novel RHAG allele, namely, c.[572G>A;707A>C], both in the proband and one of his brothers. CONCLUSIONS To our knowledge, we identified the second double-variant RHAG allele and the first one related to Rhmod phenotype. The novel allele was also confirmed to be heritable by family analyses.
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Affiliation(s)
- R W Xia
- Blood Group Reference Laboratory, Qujing Blood Center, Qujing, China
| | - C Z Xun
- Blood Group Reference Laboratory, Qujing Blood Center, Qujing, China
| | - D Xiang
- Shanghai Institute of Blood Transfusion, Shanghai Blood Center, Shanghai, China
| | - J M Zhang
- Shanghai Institute of Blood Transfusion, Shanghai Blood Center, Shanghai, China
| | - Q X Yang
- Shanghai Institute of Blood Transfusion, Shanghai Blood Center, Shanghai, China
| | - F Y Zhao
- Shanghai Institute of Blood Transfusion, Shanghai Blood Center, Shanghai, China
| | - C Wang
- Shanghai Institute of Blood Transfusion, Shanghai Blood Center, Shanghai, China
| | - Z Y Zhu
- Shanghai Institute of Blood Transfusion, Shanghai Blood Center, Shanghai, China
| | - Q Li
- Shanghai Institute of Blood Transfusion, Shanghai Blood Center, Shanghai, China
| | - L Y Ye
- Shanghai Institute of Blood Transfusion, Shanghai Blood Center, Shanghai, China
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Mu S, Cui Y, Wang W, Wang L, Xu H, Zhu O, Zhu D. A RHAG point mutation selectively disrupts Rh antigen expression. Transfus Med 2018; 29:121-127. [PMID: 29508504 DOI: 10.1111/tme.12519] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 12/29/2017] [Accepted: 02/11/2018] [Indexed: 11/27/2022]
Abstract
OBJECTIVES The aim of this study was to characterise a novel mutation in the gene encoding RhAG in order to elucidate a molecular mechanism for Rh antigen expression and spherocytosis. BACKGROUND Rhesus-associated glycoprotein (RhAG) is critical for maintaining the structure and stability of erythrocytes. Single missense mutations in the gene encoding RhAG are sufficient to induce spherocytosis and deficiencies in Rh complex formation. We report a novel missense mutation that incompletely disrupts Rh antigen expression and selectively knocks out RhD antigen expression. METHODS Blood samples were taken from a 38-year-old male, his brother, his wife and his daughter in Xi'an, China. To detect the proband's RhAG and D antigen expression, the RBC were stained with anti-D and anti-RhAG and analysed by flow cytometry. Red blood cell morphology was detected with atomic force microscopy (AFM). Genomic DNA was isolated from whole blood samples, and the RHD, RHCE and RHAG alleles were sequenced and analysed. The mutation was mapped onto a predicted crystal structure of RhAG by the I-TASSER server and visualised using PyMOL. RESULTS Morphological testing by AFM found clear evidence of spherocytosis in the proband's erythrocytes. RHAG gene sequencing identified the mutation at sequence 236G > A, resulting in a serine to asparagine substitution at residue 79 (S79N). Family survey indicated that inheriting this allele is necessary and sufficient to cause the condition. Mapping the mutation onto a predicted crystal structure of RhAG revealed the proximity of the mutation to the critical structural elements of the protein. CONCLUSIONS A novel RHAG mutation significantly lowers RhAG antigen expression and antigen-mediated agglutination intensity.
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Affiliation(s)
- S Mu
- Department of Transfusion Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
| | - Y Cui
- Department of Transfusion Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
| | - W Wang
- Department of Transfusion Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
| | - L Wang
- Department of Transfusion Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
| | - H Xu
- Shanxi Blood Center, Xi'an, China
| | - O Zhu
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA
| | - D Zhu
- Department of Transfusion Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
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Kulkarni SS, Vasantha K, Gogri H, Parchure D, Madkaikar M, Férec C, Fichou Y. First report of Rhnullindividuals in the Indian population and characterization of the underlying molecular mechanisms. Transfusion 2017; 57:1944-1948. [DOI: 10.1111/trf.14150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/27/2017] [Accepted: 03/31/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Swati S. Kulkarni
- National Institute of Immunohaematology, Indian Council of Medical Research (NIIH-ICMR); Mumbai India
| | - Kasiviswanathan Vasantha
- National Institute of Immunohaematology, Indian Council of Medical Research (NIIH-ICMR); Mumbai India
| | - Harita Gogri
- National Institute of Immunohaematology, Indian Council of Medical Research (NIIH-ICMR); Mumbai India
| | - Disha Parchure
- National Institute of Immunohaematology, Indian Council of Medical Research (NIIH-ICMR); Mumbai India
| | - Manisha Madkaikar
- National Institute of Immunohaematology, Indian Council of Medical Research (NIIH-ICMR); Mumbai India
| | - Claude Férec
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078; Brest France
- Etablissement Français du Sang Bretagne; Brest France
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Centre Hospitalier Régional Universitaire (CHRU), Hôpital Morvan; Brest France
- Faculté de Médecine et des Sciences de la Santé, Université de Bretagne Occidentale (UBO); Brest France
| | - Yann Fichou
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078; Brest France
- Etablissement Français du Sang Bretagne; Brest France
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Hou L, Yan QD, Tian L. A novel nonsense mutation in RHAG gene responsible for Rh null phenotype in a Chinese individual. Transfus Apher Sci 2017; 56:220-222. [DOI: 10.1016/j.transci.2016.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 12/01/2016] [Accepted: 12/12/2016] [Indexed: 11/30/2022]
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Silvy M, Beley S, Peyrard T, Ouchari M, Abdelkefi S, Jemni Yacoub S, Chiaroni J, Bailly P. Short duplication within theRHCEgene associated with an in cis deletedRHDcausing a Rhnullamorph phenotype in an immunized pregnant woman with anti-Rh29. Transfusion 2014; 55:1407-10. [DOI: 10.1111/trf.12937] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 09/15/2014] [Accepted: 09/30/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Monique Silvy
- Etablissement Français du Sang Alpes Méditerranée; Marseille France
- UMR 7268 ADÉS Aix-Marseille Université-EFS-CNRS; Marseille France
| | - Sophie Beley
- Etablissement Français du Sang Alpes Méditerranée; Marseille France
- UMR 7268 ADÉS Aix-Marseille Université-EFS-CNRS; Marseille France
| | - Thierry Peyrard
- Département Centre National de Référence pour les Groupes Sanguins; Institut National de la Transfusion Sanguine (INTS); Paris France
| | - Mouna Ouchari
- Centre Régional de Transfusion Sanguine; Unité de Recherche UR12SP26; Sousse Tunisia
| | - Saadia Abdelkefi
- Centre Régional de Transfusion Sanguine; Unité de Recherche UR12SP26; Sousse Tunisia
| | - Saloua Jemni Yacoub
- Centre Régional de Transfusion Sanguine; Unité de Recherche UR12SP26; Sousse Tunisia
| | - Jacques Chiaroni
- Etablissement Français du Sang Alpes Méditerranée; Marseille France
- UMR 7268 ADÉS Aix-Marseille Université-EFS-CNRS; Marseille France
| | - Pascal Bailly
- Etablissement Français du Sang Alpes Méditerranée; Marseille France
- UMR 7268 ADÉS Aix-Marseille Université-EFS-CNRS; Marseille France
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Polin H, Gaszner W, Hackl C, Danzer M, Niklas N, Gabriel C. On the trail of anti-CDE to unexpected highlights of the RHD*weak 4.3 allele in the Upper Austrian population. Vox Sang 2012; 103:130-6. [DOI: 10.1111/j.1423-0410.2012.01586.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Tian L, Song N, Yao ZQ, Huang M, Hou L. A family study of the Chinese Rhnull individual of the regulator type: a novel single missense mutation identified in RHAG gene. Transfusion 2011; 51:2686-9. [DOI: 10.1111/j.1537-2995.2011.03218.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Critical band 3 multiprotein complex interactions establish early during human erythropoiesis. Blood 2011; 118:182-191. [PMID: 21527529 DOI: 10.1182/blood-2010-10-314187] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Band 3, the major anion transport protein of human erythrocytes, forms the core of a multiprotein complex in the erythrocyte membrane. Here we studied the spatiotemporal mechanisms of band 3 multiprotein complex assembly during erythropoiesis. Significant pools of intracellular band 3 and Rh-associated glycoprotein (RhAG) were found in the basophilic erythroblast. These intracellular pools decreased in the polychromatic erythroblast, whereas surface expression increased and were lowest in the orthochromatic erythroblast and reticulocytes. Protease treatment of intact cells to remove extracellular epitopes recognized by antibodies to band 3 and RhAG was used to study surface delivery kinetics and intracellular complex composition from the proerythroblast stage to the enucleated reticulocyte. Newly synthesized band 3 and protein 4.2 interact initially in the early stages of the secretory pathway and are found associated at the plasma membrane from the basophilic stage of erythropoiesis. Although we could successfully coimmunoprecipitate Rh with RhAG from plasma membrane pools at a similar stage, no intracellular interaction between these proteins was detectable. Knockdown of RhAG during early erythropoiesis was accompanied by a concomitant drop in membrane expression of Rh polypeptides. These data are consistent with assembly of major components of the band 3 macrocomplex at an early stage during erythropoiesis.
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Huang CH, Ye M. The Rh protein family: gene evolution, membrane biology, and disease association. Cell Mol Life Sci 2010; 67:1203-18. [PMID: 19953292 PMCID: PMC11115862 DOI: 10.1007/s00018-009-0217-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 11/10/2009] [Accepted: 11/12/2009] [Indexed: 11/25/2022]
Abstract
The Rh (Rhesus) genes encode a family of conserved proteins that share a structural fold of 12 transmembrane helices with members of the major facilitator superfamily. Interest in this family has arisen from the discovery of Rh factor's involvement in hemolytic disease in the fetus and newborn, and of its homologs widely expressed in epithelial tissues. The Rh factor and Rh-associated glycoprotein (RhAG), with epithelial cousins RhBG and RhCG, form four subgroups conferring upon vertebrates a genealogical commonality. The past decade has heralded significant advances in understanding the phylogenetics, allelic diversity, crystal structure, and biological function of Rh proteins. This review describes recent progress on this family and the molecular insights gleaned from its gene evolution, membrane biology, and disease association. The focus is on its long evolutionary history and surprising structural conservation from prokaryotes to humans, pointing to the importance of its functional role, related to but distinct from ammonium transport proteins.
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Affiliation(s)
- Cheng-Han Huang
- Laboratory of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
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11
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Tilley L, Green C, Poole J, Gaskell A, Ridgwell K, Burton NM, Uchikawa M, Tsuneyama H, Ogasawara K, Akkøk CA, Daniels G. A new blood group system, RHAG: three antigens resulting from amino acid substitutions in the Rh-associated glycoprotein. Vox Sang 2009; 98:151-9. [PMID: 19744193 DOI: 10.1111/j.1423-0410.2009.01243.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND OBJECTIVES Rh-associated glycoprotein (RhAG) is closely associated with the Rh proteins in the red cell membrane. Two high frequency antigens (Duclos and DSLK) and one low frequency antigen (Ol(a)) have serological characteristics suggestive of expression on RhAG. MATERIALS AND METHODS RHAG was sequenced from the DNA of one Duclos-negative, one DSLK-negative, and two Ol(a+) individuals. Recombinant protein was expressed in HEK 293 cells. Protein models with RhAG subunits were constructed. RESULTS The original Duclos-negative patient was homozygous for RHAG 316C>G, encoding Gln106Glu. HEK 293 cells expressing Gln106Glu mutant RhAG did not react with anti-Duclos. An individual with DSLK-negative red cells was homozygous for 490A>C, encoding Lys164Gln. Two Ol(a+) members of the original Norwegian family were heterozygous for 680C>T, encoding Ser227Leu. A Japanese donor with Rh(mod) phenotype had Ol(a+) red cells and was homozygous for 680C>T. CONCLUSION The three red cell antigens encoded by RHAG form the RHAG blood group system: Duclos is RHAG1 (030001); Ol(a) is RHAG2 (030002); and DSLK is provisionally RHAG3 (030003).
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Affiliation(s)
- L Tilley
- International Blood Group Reference Laboratory and Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, UK
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Ji Q, Hashmi S, Liu Z, Zhang J, Chen Y, Huang CH. CeRh1 (rhr-1) is a dominant Rhesus gene essential for embryonic development and hypodermal function in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2006; 103:5881-6. [PMID: 16595629 PMCID: PMC1458667 DOI: 10.1073/pnas.0600901103] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Indexed: 01/16/2023] Open
Abstract
Rhesus (Rh) proteins share a conserved 12-transmembrane topology and specify a family of putative CO(2) channels found in diverse species from microbes to human, but their functional essentiality and physiological importance in metazoans is unknown. To address this key issue and analyze Rh-engaged physiologic processes, we sought to explore model organisms with fewer Rh genes yet are tractable to genetic manipulations. In this article, we describe the identification in nematodes of two Rh homologues that are highly conserved and similar to human Rh glycoproteins, and we focus on their characterization in Caenorhabditis elegans. RNA analysis revealed that CeRh1 is abundantly expressed in all developmental stages, with highest levels in adults, whereas CeRh2 shows a differential and much lower expression pattern. In transient expression in human cells, both CeRh1 and CeRh2-GFP fusion proteins were routed to the plasma membrane. Transgenic analysis with GFP or LacZ-fusion reporters showed that CeRh1 is mainly expressed in hypodermal tissue, although it is also in other cell types. Mutagenesis analysis using deletion constructs mapped a minimal promoter region driving CeRh1 gene expression. Although CeRh2 was dispensable, RNA interference with CeRh1 caused a lethal phenotype mainly affecting late stages of C. elegans embryonic development, which could be rescued by the CbRh1 homologue from the worm Caenorhabditis briggsae. Taken together, our data provide direct evidence for the essentiality of the CeRh1 gene in C. elegans, establishing a useful animal model for investigating CO(2) channel function by cross-species complementation.
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Affiliation(s)
- Qiongmei Ji
- Laboratories of *Biochemistry and Molecular Genetics
| | - Sarwar Hashmi
- Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, 310 East 67th Street, New York, NY 10021
| | - Zhi Liu
- Laboratories of *Biochemistry and Molecular Genetics
| | - Jun Zhang
- Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, 310 East 67th Street, New York, NY 10021
| | - Ying Chen
- Laboratories of *Biochemistry and Molecular Genetics
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Tada T, Ohmori M, Iida H. Molecular dissection of the hydrophobic segments H3 and H4 of the yeast Ca2+ channel component Mid1. J Biol Chem 2003; 278:9647-54. [PMID: 12514173 DOI: 10.1074/jbc.m206993200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Saccharomyces cerevisiae MID1 gene product, Mid1, is composed of 548 amino acid residues, has four relatively hydrophobic segments named H1-H4, and functions as a Ca(2+)-permeable, stretch-activated channel when expressed in mammalian cells. In some conditions Mid1 cooperates with Cch1, a yeast homolog of the alpha1 subunit of mammalian voltage-gated channels. To identify the important regions or amino acid residues necessary for Mid1 function, we employed in vitro site-directed mutagenesis on H3 and H4 of Mid1 and expressed the resulting mutant genes in a mid1 null mutant to examine whether the mutant gene products are functional or not in vivo. Mutant Mid1 proteins lacking the whole H3 or H4 segment, H3De or H4De, did not complement the lethality and low Ca(2+) accumulation activity of the mid1 mutant, although their localization and contents appeared to be normal, indicating that H3 and H4 are required for Mid1 function itself. Single amino acid exchange experiments on individual amino acid residues of H3 and H4 showed that 10 of 20 residues in H3 and 14 of 23 residues in H4 were important for the normal function of Mid1. In particular, we found four severe loss-of-function mutations, D341E, F356S, C373D, and C373R, and two interesting mutations leading to a high level of Ca(2+) accumulation with a slightly low complementing activity, G342A and Y355A. The importance of these amino acid residues will be discussed.
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Affiliation(s)
- Tomoko Tada
- Department of Biology, Tokyo Gakugei University, Tokyo 184-8501, Japan
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Chen BS, Xu ZX, Xu X, Cai Y, Han YL, Wang J, Xia SH, Hu H, Wei F, Wu M, Wang MR. RhCG is downregulated in oesophageal squamous cell carcinomas, but expressed in multiple squamous epithelia. Eur J Cancer 2002; 38:1927-36. [PMID: 12204676 DOI: 10.1016/s0959-8049(02)00190-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To better understand the molecular events underlying the development of oesophageal cancer, we have isolated the genes dysregulated in primary oesophageal cancer tissues using a modified differential display polymerase chain reaction (DD-PCR). In the present study, a gene designated C15orf6 was identified. The C15orf6 gene, encompassing 25 kb, is composed of 11 exons with a mRNA of 1948 bp. Database searching showed that C15orf6 was 100% homologous to the Rh type C-glycoprotein (RhCG) with the same open reading frame, but 16 bp longer than RhCG at the 5'-end. The gene was highly expressed in human oesophagus, cervix, oral cavity, skin and kidney, but undetectable in the other 14 adult normal tissues examined. Northern blot, RT-PCR and western blot analysis showed that RhCG/C15orf6 was frequently lost or dramatically reduced in primary oesophageal cancer tissues (30/34) compared with the corresponding normal oesophageal mucosa. Three oesophageal-cancer cell lines tested lacked RhCG/C15orf6 expression. Immunohistochemistry revealed that in normal oesophageal tissues, RhCG/C15orf6 was mainly expressed in the plasma membrane of the epithelial cells. In addition, Rh-associated glycoprotein (RhAG) expression was also commonly silenced in both oesophageal cancer cell lines (2/3) and primary oesophageal cancer tissues (11/13). To our knowledge, this is the first time that RhAG expression has been seen in oesophageal epithelium and extends the functional role of the RhAG protein beyond the erythrocyte. These data suggest that inactivation of RhCG/C15orf6 and RhAG occurs frequently during the development of human oesophageal cancer.
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Affiliation(s)
- Bao-Sheng Chen
- National Laboratory of Molecular Oncology, Cancer Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
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Abstract
Rh molecular biology has made many advances since the first Rh cDNA was cloned in 1990. This review summarizes the current knowledge concerning the molecular basis of Rh antigenicity, D-epitope expression, and the structures of the Rh genes and proteins. Although many recent reviews have appeared regarding these subjects, advances in Rh protein function that have been published within the last 12 months have had a fundamental impact on the future direction of Rh research. In November 2000, an article described the role of Rh proteins in ammonium transport, which has remained undescribed in vertebrates, except for non-specific transport via K+ channels. The recent identification of nonerythroid Rh proteins, their expression in diverse tissues, and notably polarized epithelial and endothelial cells will be of broad functional significance and will greatly increase our understanding of the role of Rh in ammonium transport and the biology of ammonium metabolism as a whole. The advances in Rh molecular genetics have enabled the development of diagnostic tests in the clinic. At present, this is largely confined to the prenatal diagnosis of fetal blood group status in alloimmunized pregnancies, but could be extended to the noninvasive prenatal testing of all D-negative pregnant women and eventually, perhaps, to all patient and donor blood.
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Affiliation(s)
- N D Avent
- Centre for Research in Biomedicine, University of the West of England, Bristol, United Kingdom.
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Liu Z, Chen Y, Mo R, Hui C, Cheng JF, Mohandas N, Huang CH. Characterization of human RhCG and mouse Rhcg as novel nonerythroid Rh glycoprotein homologues predominantly expressed in kidney and testis. J Biol Chem 2000; 275:25641-51. [PMID: 10852913 DOI: 10.1074/jbc.m003353200] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In mammals, the Rh family includes the variable Rh polypeptides and invariant RhAG glycoprotein. These polytopic proteins are confined to the erythroid lineage and are assembled into a multisubunit complex essential for Rh antigen expression and plasma membrane integrity. Here, we report the characterization of RhCG and Rhcg, a pair of novel Rh homologues present in human and mouse nonerythroid tissues. Despite sharing a notable similarity to the erythroid forms, including the 12-transmembrane topological fold, the RHCG/Rhcg pair is distinct in chromosome location, genomic organization, promoter structure, and tissue-specific expression. RHCG and Rhcg map at 15q25 of human chromosome 15 and the long arm of mouse chromosome 7, respectively, each having 11 exons and a CpG-rich promoter. Northern blots detected kidney and testis as the major organs of RHCG or Rhcg expression. In situ hybridization revealed strong expression of Rhcg in the kidney collecting tubules and testis seminiferous tubules. Confocal imaging of transiently expressed green fluorescence protein fusion proteins localized RhCG exclusively to the plasma membrane, a distribution confirmed by cellular fractionation and Western blot analysis. In vitro translation and ex vivo expression showed that RhCG carries a complex N-glycan, probably at the (48)NLS(50) sequon of exoloop 1. These results pinpoint RhCG and Rhcg as novel polytopic membrane glycoproteins that may function as epithelial transporters maintaining normal homeostatic conditions in kidney and testis.
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Affiliation(s)
- Z Liu
- Laboratory of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10021, USA
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Abstract
The Rh (Rhesus) blood group system is the most complex of the known human blood group polymorphisms. The expression of its antigens is controlled by a two-component genetic system consisting of RH and RHAG loci, which encode Rh30 polypeptides and Rh50 glycoprotein, respectively. Over the past decade, there has been a rapid advance in knowledge of the biochemistry, molecular biology, and genetics of the Rh genes and proteins. The primary structures of D and CcEe antigens have become well understood and the molecular genetic basis of a vast array of phenotype polymorphisms has been delineated. The identification of various molecular defects associated with Rh deficiency syndrome clarifies the nature of the amorph, suppressor, and modifier genes. The observed mutation spectrum defines a basic set of components essential for Rh complex assembly in the erythrocyte membrane. The resulting molecular information, combined with new experimental tools, is helping to dissect the fine structure of Rh antigens in terms of epitope mapping. The discovery of novel Rh homologs in primitive organisms and in nonerythroid tissues opens new avenues of research beyond the scope of erythrocytes and Rh antigens. This review provides an update on the Rh family in antigen expression, phenotype diversity, and disease association.
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Affiliation(s)
- C H Huang
- Laboratory of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institute, New York Blood Center, New York 10021, USA
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19
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Abstract
The Rh blood group system is one of the most polymorphic and immunogenic systems known in humans. In the past decade, intense investigation has yielded considerable knowledge of the molecular background of this system. The genes encoding 2 distinct Rh proteins that carry C or c together with either E or e antigens, and the D antigen, have been cloned, and the molecular bases of many of the antigens and of the phenotypes have been determined. A related protein, the Rh glycoprotein is essential for assembly of the Rh protein complex in the erythrocyte membrane and for expression of Rh antigens. The purpose of this review is to provide an overview of several aspects of the Rh blood group system, including the confusing terminology, progress in molecular understanding, and how this developing knowledge can be used in the clinical setting. Extensive documentation is provided to enable the interested reader to obtain further information.
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Abstract
Rhesus (Rh) antigens are defined by a complex association of membrane polypeptides that are missing or severely deficient from the red cells of rare Rhnull individuals who suffer a clinical syndrome of varying severity characterized by abnormalities of the red cell shape, cation transport and membrane phospholipid organization. The Rhnull phenotype is an inherited condition that may arise from homozygosity either for a 'suppressor' gene unrelated to the RH locus ('regulator type') or for a silent allele at the RH locus itself ('amorph type'). A current model suggests that the proteins of the Rh complex (Rh, RhAG, CD47, LW, GPB) are assembled by non-covalent bonds and that it is not assembled or transported to the cell surface when one subunit is missing. Rh and RhAG proteins belong to the same protein family and are quantitatively the major components that form the core of the complex, which is firmly linked to the membrane skeleton. Molecular analysis of Rhnull individuals has revealed that abnormalities occur only at the RHAG and RH loci, without alteration of the genes encoding the accessory chains. Mutations of the RHAG gene, but not of RH, occur in all Rhnull individuals of the regulator type (including Rhmod) investigated so far (13 cases), strongly suggesting that RHAG mutants act as 'suppressors' and not as transcriptional regulators of the RH genes and that variable expression of the RHAG alleles may account for the Rhmod phenotypes (exhibiting weak expression of Rh antigens). Conversely, mutations of the RHCE gene, but not of RHAG, occur in two unrelated Rhnull individuals of the amorph type, supporting the view that RH mutants result from a 'silent' allele at the RH locus. These findings strongly support the Rh complex model since when either the Rh or RhAG protein is missing, the assembly and/or transport of the Rh complex is defective. Transcriptional as well as post-transcriptional mechanisms may account for the molecular abnormalities, but experimental evidence based on expression models is required to test these hypotheses, in the hope that they may help to clarify the biological role of the Rh proteins in the red cell membrane.
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Affiliation(s)
- J P Cartron
- INSERM Unité U76, Institut National de la Transfusion Sanguine, Paris, France
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Huang CH, Cheng G, Liu Z, Chen Y, Reid ME, Halverson G, Okubo Y. Molecular basis for Rh(null) syndrome: identification of three new missense mutations in the Rh50 glycoprotein gene. Am J Hematol 1999; 62:25-32. [PMID: 10467273 DOI: 10.1002/(sici)1096-8652(199909)62:1<25::aid-ajh5>3.0.co;2-k] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Rh(null) is a rare autosomal recessive disorder characterized by an absence of Rh antigens and a varying degree of hemolytic anemia and spherostomatocytosis. We report studies of two Japanese Rh(null) cases and describe three new missense mutations of RHAG, the locus that encodes Rh50 glycoprotein and modulates Rh antigen expression. In Rh(null)(HT), RHAG harbored in exon 6 two G-->A transitions, GTT-->ATT and GGA-->AGA, which cause Val(270)-->Ile and Gly(280)-->Arg substitutions, respectively. These missense mutations were cotransmitted from the propositus to the children and were predicted to reside in endoloop 5 and transmembrane (TM) segment 9, respectively. In Rh(null)(WO), RHAG contained in exon 9 a single G-->T transversion, GGT-->GTT, which caused a Gly(380)-->Val missense change in TM12 segment. The G-->T transversion, which is located at the +1 position of exon 9, had also affected pre-mRNA splicing and caused partial exon skipping. Although both Rh(null) cases had a structurally normal RH antigen locus, hemagglutination and immunoblotting showed no expression of Rh antigens or proteins. These results correlate each mutation with a structural defect in the respective TM domain of Rh50 glycoprotein.
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Affiliation(s)
- C H Huang
- Laboratory of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York 10021, USA.
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22
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Takenaka K, Sakai H, Yamakawa H, Yoshimura S, Kumagai M, Yamakawa H, Nakashima S, Nozawa Y, Sakai N. Polymorphism of the endoglin gene in patients with intracranial saccular aneurysms. J Neurosurg 1999; 90:935-8. [PMID: 10223461 DOI: 10.3171/jns.1999.90.5.0935] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Endoglin, a transforming growth factor beta-binding protein, is a glycoprotein expressed on the surface of human vascular endothelial cells. Mutations of this gene are responsible for hereditary hemorrhagic telangiectasis and are associated with sporadic intracerebral hemorrhage as a risk factor. The purpose of this study was to examine the polymorphism of this gene in patients with intracranial aneurysms. METHODS The authors identified the mutations and insertion polymorphism around exon 7 of the endoglin gene in 82 patients with intracranial saccular aneurysms (aneurysm group) and 114 control volunteers (control group). A 6-base insertion (GGGGGA) was found in intron 7 at 26 bases beyond the 3' end of exon 7. The homozygous insertion of intron 7 of the gene was present in 20.7% of the aneurysm group compared with 6.1% of the control group (chi2 = 9.837, p = 0.0073). The insertion allele frequency was significantly higher in the aneurysm group (67 [40.8%] of 164) than that in the control group (63 [27.6%] of 228) (chi2 = 7.48, p = 0.0062). The most notable clinical characteristic of the 17 patients with homozygous insertion in the aneurysm group was the relatively high percentage of patients with hypertension and of those with multiple aneurysms. CONCLUSIONS The data provide evidence of an association between aneurysm development and a polymorphism at a genetic variant of endoglin in patients with these lesions.
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Affiliation(s)
- K Takenaka
- Department of Neurosurgery, Gifu University School of Medicine, Gifu City, Japan.
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Huang C, Cheng GJ, Reid ME, Chen Y. Rhmod syndrome: a family study of the translation-initiator mutation in the Rh50 glycoprotein gene. Am J Hum Genet 1999; 64:108-17. [PMID: 9915949 PMCID: PMC1377708 DOI: 10.1086/302215] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Rhmod syndrome is a rare genetic disorder thought to result from mutations at a "modifier" but not at the suppressor underlying the regulator type of Rhnull disease. We studied this disorder in a Jewish family with a consanguineous background and analyzed RH and RHAG, the two loci that control Rh-antigen expression and Rh-complex assembly. Despite the presence of a d (D-negative) haplotype, no other gross alteration was found at RH, and cDNA sequencing showed a normal structure for D, Ce, and ce Rh transcripts in family members. However, analysis of RHAG transcript, which encodes Rh50 glycoprotein, identified a single G-->T transversion in the initiation codon, causing a missense amino acid change (ATG[Met]-->ATT[Ile]). This point mutation also occurred in the genomic region spanning exon 1 of RHAG, and its genotypic status in the mother and two children was confirmed by analysis of single-strand conformation polymorphism. Although blood typing showed a very weak expression of Rh antigens, immunoblotting barely detected the Rh proteins in the Rhmod membrane. In vitro transcription-coupled translation assays showed that the initiator mutants of Rhmod-but not those of the wild type-could be translated from ATG codons downstream. Our findings point to incomplete penetrance of the Rhmod mutation, in the form of "leaky" translation, leading to some posttranslational defects affecting the structure, interaction, and processing of Rh50 glycoprotein.
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Affiliation(s)
- C Huang
- Laboratory of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10021, USA.
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