Inter-Research
Diseases of Aquatic Organisms

ABSTRACT: This study reports the first serine protease gene(s) isolated from Perkinsus marinus. Using universal primers, a 518 bp subtilisin-like serine protease gene fragment was amplified from P. marinus genomic DNA and used as a probe to screen a l-phage P. marinus genomic library; 2 different l-phage clones hybridized to the digoxigenin(DIG)-labeled subtilisin-like gene fragment. Following subcloning and sequencing of the larger DNA fragment, a 1254 bp open reading frame was identified and later confirmed, by 5' and 3' random amplification of cDNA ends (RACE) and northern blot analysis, to contain the entire coding-region sequence. Sequence analysis of the 3' RACE results from 2 isolate cultures, VA-2 (P-1) and LA 10-1, revealed multiple polymorphic sites within and among isolates. We identified 2 different types of cDNA clones with 95.53% nucleotide sequence similarity, suggesting the possibility of 2 closely related genes within the P. marinus genome. Southern blot analysis of genomic DNA from 12 genetically distinct P. marinus isolate cultures revealed 2 different banding patterns among isolates.

KEY WORDS: Perkinsus marinus · Subtilisin · Serine protease

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Published in DAO Vol. 57, No. 1-2 (2003) on December 3
Print ISSN: 0177-5103; Online ISSN: 1616-1580. Copyright © Inter-Research, Oldendorf/Luhe, 2003