A unique chicken B-creatine kinase gene gives rise to two B-creatine kinase isoproteins with distinct N termini by alternative splicing.
In the chicken, a high degree of heterogeneity at the protein level has been reported for the creatine kinase-type B (B-CK). Here we show that the two B-CK isoproteins, Ba- and Bb-CK, are encoded by two mRNAs, which are derived from a single copy gene by a stochastic alternative splicing mechanism. The transcription of the single hnRNA is directed by a complex promoter region containing a stretch of sequences which is highly conserved among all the B-CK genes known to date. This stretch encompasses a putative binding site for the TA-rich DNA-binding protein (Hobson, G. M., Mitchell, M. T., Molloy, G. R., and Pearson, M. L. (1988) Nucleic Acids Res. 16, 8925-8944) which is located in the distal part of the promoter region, while the proximal portion containing the TATA-box used in vivo is not conserved between chicken and mammals. The two isoproteins arising from this gene contain distinct N-terminal portions. According to comparative analysis, Bb-CK is the form which is homologous to the mammalian B-CKs, whereas Ba-CK shows some sequence features unique among all other vertebrate cytosolic creatine kinases characterized so far.
Wirz
T
T
Institute for Cell Biology, Swiss Federal Institute of Technology, Zurich.
Brändle
U
U
Soldati
T
T
Hossle
J P
JP
Perriard
J C
JC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002645:Chickens; D003001:Cloning, Molecular; D003402:Creatine Kinase / Q000235:genetics*; D004247:DNA / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D015342:DNA Probes; D015723:Gene Library; D005796:Genes; D007527:Isoenzymes; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics*; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D015342:DNA Probes; D007527:Isoenzymes; D012333:RNA, Messenger; D004247:DNA; D003402:Creatine Kinase