Recently, Fab fragment gene was discovered in the Asterid genome (Asterias rubens genome).More recently was found the Fab fragment gene in the Ophiocomina nigra genome with an e-value of 3,00E-12 and 89,38 identity ( Homo sapiens/0.nigra).This discovery corroborates the presence of a primitive antibody in Ophuirids.
Keywords: Invertebrate, Ophuirids, Ophiocomina Nigra, Fab Fragment Gene, Primitive Antibody
The purpose of this paper is to draw attention to the emergence of primitive antibody(1,2) in two classes of Echinodermata :
The Asterids and the Ophuirids. In the sea star primitive antibody, the presence of Fab fragment gene occured(3)
The aim of this communication is to look for Fab fragment gene in the genome of Ophiocomina nigra.
Materials and Methods
Ophiocomina nigra was otained from the Biology Station of Roscoff.
a) Ophiocomina nigra and its preparation to obtain mRNA have already been described(2).Furthermore quality controls were made.
b) It is useful to add that :
Transcriptome was assembled from RNA-Seq fastq files using Trinity
v2.1.1(4) with default parameters. A BLAST database was created with the assembled transcripts using makeblastdb application from ncbi-blast+ (v2.2.31+). The sequences of transcripts of interest were then blasted against this database using blastn application from ncbi-blast+(5) with parameter word_size 7.
The transcriptome presents the sequence of Fab fragment gene(e-value:3,00E-12)
The identity of the sequence with Homo sapiens is of 89,38 %.
The e-value is highly significant..
In Asterias rubens Fab fragment gene was clearly expressed
such as Fc receptor gene(3) We ‘ll retain the fact that in Ophiocomina nigra, Fab fragment gene appears too in the sequencing.It corroborates indirectly, by its presence, the explanation of a primitive antibody, in ophuirids (Echinodermata)
We recall that Echinodermata shows immune specific humoral
reactions, at least for asterids and ophuirids(1,6) : it makes their originality.