TY - JOUR
T1 - Characterization of recessive RYR1 mutations in core myopathies
AU - Zhou, Haiyan
AU - Yamaguchi, Naohiro
AU - Xu, Le
AU - Wang, Ying
AU - Sewry, Caroline
AU - Jungbluth, Heinz
AU - Zorzato, Francesco
AU - Bertini, Enrico
AU - Muntoni, Francesco
AU - Meissner, Gerhard
AU - Treves, Susan
PY - 2006/9/15
Y1 - 2006/9/15
N2 - We have characterized at the molecular level, three families with core myopathies carrying apparent recessive mutations in their RYR1 gene and studied the pharmacological properties of myotubes carrying endogenous mutations as well as the properties of mutant channels expressed in HEK293 cells. The proband of family 1 carried p.Ala1577Thr + p.Gly2060Cys in trans, having inherited a mutation from each parent. Immunoblot analysis of proteins from the patient's skeletal muscle revealed low levels of ryanodine receptor (RyR1) but neither substitution alone or in combination affected the functional properties of RyR1 channels in a discernable way. Two affected siblings in family 2 carried p.Arg109Trp + p.Met485Val substitutions in cis, inherited from the unaffected father. Interestingly, both affected siblings only transcribed the mutated paternal allele in skeletal muscle, whereas the maternal allele was silent. Single-channel measurements showed that recombinant, mutant RyR1 channels carrying both substitutions lost the ability to conduct Ca2+. In this case as well, low levels of RyR1 were present in skeletal muscle extracts. The proband of family 3 carried p.Ser71Tyr + p.Asn2283His substitutions in trans. Recombinant channels with Asn2283His substitution showed an increased activity, whereas recombinant channels with p.Ser71Tyr + p.Asn2283His substitution lost activity upon isolation. Taken together, our data suggest major differences in the ways RYR1 mutations may affect patients with core myopathies, by compromising RyR1 protein expression, stability and/or activity.
AB - We have characterized at the molecular level, three families with core myopathies carrying apparent recessive mutations in their RYR1 gene and studied the pharmacological properties of myotubes carrying endogenous mutations as well as the properties of mutant channels expressed in HEK293 cells. The proband of family 1 carried p.Ala1577Thr + p.Gly2060Cys in trans, having inherited a mutation from each parent. Immunoblot analysis of proteins from the patient's skeletal muscle revealed low levels of ryanodine receptor (RyR1) but neither substitution alone or in combination affected the functional properties of RyR1 channels in a discernable way. Two affected siblings in family 2 carried p.Arg109Trp + p.Met485Val substitutions in cis, inherited from the unaffected father. Interestingly, both affected siblings only transcribed the mutated paternal allele in skeletal muscle, whereas the maternal allele was silent. Single-channel measurements showed that recombinant, mutant RyR1 channels carrying both substitutions lost the ability to conduct Ca2+. In this case as well, low levels of RyR1 were present in skeletal muscle extracts. The proband of family 3 carried p.Ser71Tyr + p.Asn2283His substitutions in trans. Recombinant channels with Asn2283His substitution showed an increased activity, whereas recombinant channels with p.Ser71Tyr + p.Asn2283His substitution lost activity upon isolation. Taken together, our data suggest major differences in the ways RYR1 mutations may affect patients with core myopathies, by compromising RyR1 protein expression, stability and/or activity.
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U2 - 10.1093/hmg/ddl221
DO - 10.1093/hmg/ddl221
M3 - Article
C2 - 16940308
AN - SCOPUS:33748752700
VL - 15
SP - 2791
EP - 2803
JO - Human Molecular Genetics
JF - Human Molecular Genetics
SN - 0964-6906
IS - 18
ER -