Nucleic Acids Research, 1985, Vol. 13, No. 6 1817-1828
© 1985
Articles |
Complete nucleotide sequence of mRNA for caerulein precursor from Xenopus skin: the mRNA contains an unusual repetitive structure
Tsukuba Research Laboratories, Eisai Co. Ltd. 5-1-3 Tokodai, Toyosato-machi, Tsukuba-gun, Ibaraki 300-26, Japan
Received February 5, 1985. Accepted March 1, 1985.
The complete nucleotide sequence of mRNA for caerulein precursor in the skin of Xenopus laevis was determined. The sequence was composed of 705 bp of coding region, accounting for 234 amino acids, 58 bp of 5'-untranslated region and 158 bp of 3'-untranslated region containing two putative poly(A) signals. It coded for four caerulein peptides interspersed with three 147 bp segments (intercaerulein segment; ICS). Analyses of several caerulein encoding cDNAs revealed some interesting features of caerulein mRNA species, which were highly heterogenous and consisted of a repetition of two fundamental RNA sequences, a 45-nucleotide caerulein fragment and a 147-nucleotide ICS. The result of Northern blotting indicated that caerulein mRNA was only present in frog skin, not in stomach, upper intestine or liver. It appears that caeruelin has different physiological function(s) from mammlian gastrin and cholecystokinin-pancreozymin (CCK). The relationship of caerulein to mammalian gastrointestinal hormones is discussed.