Different exon-intron organizations of the genes for two astacin-like proteases, high choriolytic enzyme (choriolysin H) and low choriolytic enzyme (choriolysin L), the constituents of the fish hatching enzyme

Shigeki Yasumasu, Hiraku Shimada, Keiji Inohaya, Ken Yamazaki, Ichiro Iuchi, Ikao Yasumasu, Kenjiro Yamagami

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The hatching enzyme of the teleost, Oryzias latipes, is composed of two proteases, high choriolytic enzyme (choriolysin H, HCE) and low choriolytic enzyme (choriolysin L, LCE), which are similar in some enzymological characteristics and protein structure (55% identity in amino acid sequence) and belong to the astacin family. Two isoforms of HCE are detected. In the present study, the genes for HCE and LCE were isolated from the genomic library constructed from DNA of the inbred drR strain fish. In contrast to the close similarity of the enzymes, there was a marked difference in their gene organization. The LCE gene was a single copy gene and composed of eight exons interrupted by seven introns. The HCE genes were multicopy genes and lacked introns. In the haploid genome of the drR strain fish, there are eight HCE genes, seven of which were cloned. Each HCE gene was identified as that for either of the two isoforms of HCE. 5′ flanking regions of the LCE gene and the HCE genes had consensus TATA box sequences, but not CAT box nor GC box sequences. The big difference in the exon-intron organization between the HCE genes and the LCE gene is discussed from an evolutionary viewpoint.

Original languageEnglish
Pages (from-to)752-758
Number of pages7
JournalEuropean Journal of Biochemistry
Issue number3
Publication statusPublished - 1996 Jan 1



  • Astacin family
  • Gene structure
  • Hatching enzyme
  • Intron-less gene
  • Teleost

ASJC Scopus subject areas

  • Biochemistry

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