Mapping of two genes encoding isoforms of the actin binding protein ABP-280, a dystrophin like protein, to Xq28 and to chromosome 7.
ABP-280 is a ubiquitous actin binding protein present in the cytoskeleton of many different cell types. ABP-280 was mapped to distal Xq28, 50-60 kb downstream of the Green Colour Pigment (GCP) genes. To establish if ABP-280 may be a candidate for one of the muscle disease localized by linkage analysis to distal Xq28 we looked for alternative forms of ABP-280 mRNA. Several different ABP-280 mRNAs were indeed identified: two are X-linked and are produced by alternative splicing of a small exon of 24 nucleotides. At least one additional gene encoding a RNA more than 70% identical to ABP-280 in the 1700 bp sequenced has also been found. It was mapped to chromosome 7. While both forms of the X-linked ABP-280 are ubiquitous, the gene on chromosome 7 is highly expressed only in skeletal muscle and heart. The two genes were therefore excellent candidates for the X-linked and for the autosomal dominant form of the Emery-Dreifuss Muscular Dystrophy (EDMD) both of which have been described. So far, however we were unable to demonstrate mutations in the coding region or affecting the alternative splicing of the X-linked form of ABP-280, in several patients studied, and we think that it is quite unlikely that this is the gene responsible for EDMD.
Maestrini
E
E
Istituto di Genetica Biochimica ed Evoluzionistica, CNR, Pavia, Italy.
Patrosso
C
C
Mancini
M
M
Rivella
S
S
Rocchi
M
M
Repetto
M
M
Villa
A
A
Frattini
A
A
Zoppè
M
M
Vezzoni
P
P
D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D002874:Chromosome Mapping; D002897:Chromosomes, Human, Pair 7; D003001:Cloning, Molecular; D003285:Contractile Proteins / Q000235:genetics*; D004247:DNA / Q000235:genetics; D064448:Filamins; D005796:Genes; D006367:HeLa Cells; D006801:Humans; D008297:Male; D008840:Microfilament Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics*; D009136:Muscular Dystrophies / Q000145:classification / Q000235:genetics*; D009206:Myocardium / Q000378:metabolism; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D012194:RNA-Directed DNA Polymerase; D014960:X Chromosome
D002352:Carrier Proteins; D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D009124:Muscle Proteins; D004247:DNA; D012194:RNA-Directed DNA Polymerase