HUMAN TENASCIN-R - COMPLETE PRIMARY STRUCTURE, PRE-MESSENGER-RNA ALTERNATIVE SPLICING AND GENE LOCALIZATION ON CHROMOSOME 1Q23-Q24

We have established the primary structure of human tenascin-R (TN-R), a component of the extracellular matrix of the central nervous system, by sequencing cDNA clones which cover its complete coding region. The deduced amino acid sequence of human TN-R (1358 amino acids) showed a homology to chicken and rat TN-R of 75 and 93%, respectively. By reve rse transcriptase-polymerase chain reaction we have studied the existe nce of TN-R isoforms generated by pre-mRNA alternative splicing in var ious human astrocytomas and meningiomas. Our findings demonstrate the existence of a human isoform in which one fibronectin-like repeat is o mitted. Northern blot analysis of the poly(A)-rich RNA from different tissues showed two mRNAs having sizes of about 10 and 11 kilobases. Us ing DNA from a panel of human-hamster and human-mouse somatic cell hyb rids and by fluorescence in situ hybridization, we have assigned the g ene for human TN-R to the region 1q23-q24. The mouse mutation loop-tai l (Lp), which has been proposed as a model for human neural tube defec ts, maps to region of mouse chromosome 1 syntenic with human 1q23-q24.