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Two type XVII collagen (BP180) mRNA transcripts in human keratinocytes: a long and a short form
Author(s) -
Katalin Molnár,
Gerrit van der Steege,
Marcel F. Jonkman,
Miranda Nijenhuis,
S. Husz,
J. B. Van Der Meer,
Hendrikus Pas
Publication year - 2000
Publication title -
clinical and experimental dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 78
eISSN - 1365-2230
pISSN - 0307-6938
DOI - 10.1046/j.1365-2230.2000.00578.x
Subject(s) - untranslated region , messenger rna , microbiology and biotechnology , biology , northern blot , exon , alternative splicing , gene , rna splicing , gene expression , rna , genetics
We have analysed BP180 mRNA expression in normal human keratinocytes. Here we report the presence in normal keratinocytes of two COL17A1 transcripts which differ by 0.6 kb in length. Both mRNAs hybridized on Northern blot with probes directed to sequences encoding intracellular and extracellular fragments of BP180. By blast homology search alignments we extended the 3′ untranslated region (3′UTR) of the known BP180 mRNA sequence by 877 bases to completion. Three of 20 cDNAs identified by blast searches contained a 610 bp deletion in this new 3′UTR sequence. Northern blot analysis with a probe complementary to this deleted sequence showed binding only to the larger mRNA. The deletion of 610 nucleotides in the smaller mRNA was verified by reverse transcription–PCR and sequencing. Genomic PCR showed the new sequence to be an extension of exon 56 of the COL17A1 gene which suggests that the second mRNA is generated by differential splicing. In normal keratinocytes the level of the smaller transcript was 5–15% of that of the larger transcript whereas in a squamous cell carcinoma cell line this ratio was reversed, the smaller mRNA being three times more abundant than the larger mRNA. The biological significance of this newly identified transcript in protein synthesis and tissue expression or in cell differentiation, proliferation or adhesion is as yet unknown.