Japanese Lamprey (lampetra Japonica), Oral Gland Expressed Sequence Tag (est) Analysis

Lamprey was one kind of animal in the class Cyclostomata. It was an especial one with specialized organisms because of its half parasitic life. People concentrated on more morphology respects to the research of the lamprey for a long time, but the research of genomics and even Proteomics is a blank.A cDNA library (2.1×10⁶ pfu/mL) was constructed from the oral gland of Lampetra japonica follow the method which found by Gubler and Hoffman. After random selection of clones for sequencing, 1323 clones with inserts longer than 100bp and with good chromato-grams were obtained. Using BlastX and BlastN programs, we found 653 ESTs (49.36%) that shared significant homology with known sequences in protein or nucleotide databases of NCBI, including 328 ESTs homologous to know sequences of Petromazonidae animals. These ESTs were classified into 11 different functional categories, the highest proportion of which was related to protein synthesis (27.9%). Out of the 1323 ESTs, 162 non-redundant contigs were assembled from 547 sequences after alignment using Sequencher^TM software at the threshold of more than 90% homoloy over a minimum of 20 base pairs. There were eight full-length cDNAs with complete open reading frame. One of them was confirmed as the plasma albumin (precursor) of Lampetra japonica .Further studies on the ESTs of the library may be helpful to elucidate the components of Lampetra japonica oral gland and to understand the function of those protein at the molecular level.