The transcriptome of the Ophuirid : Ophiocomina nigra IGKappa gene which has been discovered recently(1).Since it was synthesized de novo and cloned in a pUC-GW-Kan plasmid (2) which was a gift of Bo Huang laboratories+.

Materials :

The original sequence of the Ophuirid IGKappa gene, after cloning, was the following in 5’-3’ :

KEYWORDS : Homo sapiens, Ophiocomina nigra  IGKappa gene etc

Original sequence:

GAGGAACTGCTCAGTTAGGACCCAGACGGAACCATGGAAGCCCCAGCGCAGCTTCTCTTCCTCCTGCTACTCTGGCTCCCAGATACCACTGGAGAAATAGTGATGACGCAGTCTCCAGCCACCCTGTCTGTGTCTCCAGGGGAAAGAGCCACCCTCTCCTGCAGGGCCAGTCAGAGTGTTACCAGCAACTTAGCCTGGTACCAGCAGACACCTGGGCAGTCTCCCAGGCTCGTCATCTATGGTGCATCCAGCAGGGCCAGTGGTGTCCCAGCCAGGTTCAGTGGCAGTGGGTCTGGGACAGAGTTCACTCTCACCATCAGCAGCCTGCAGTCTGAAGATTTTGCAGTTTATTACTGTCAGCAGTATAATAAGTGGCCGCACACTTTTGGCCAGGGGACCAAGCTGGACATCAAACGAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGGGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAGAGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAGAGGGAGAAGTGCCCCCACCTGCTCCTCAGTTCCAGCCTGACCCCCTCCCATCCTTTGGCCTCTGACCCTTTTTCCACAGGGGACCTACCCCTATTGCGGTCCTCCAGCTCATCTTTCACCTCACCCCCCTCCTCCTCCTTGGCTTTAATTATGCTAATGTTGGAGGAGAATGAATAAATAAAGTGAATCTTTGCAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

On the other hand we present,  an anti-HRP  (Horse-Radish peroxydase)  protein in the Ophuirid : Ophiocomina nigra, (Fig .1) (3)

It results from immunization of O.nigra to HRP. We notice some plasmolymphocytic cells , in photon microscopy, which have reacted positively (brown coloration) to HRP : HRP which is revealed by diaminobenzidin. These « precipates » may correspond to «  Primitive Immunoglobulins » from Invertebrates.

 Results andConclusion :

The original gene, the original protein issued from this last one share total identity with Homo sapiens immunoglobulin kappa locus, mRNA (cDNA clone MGC:22645 IMAGE:4700961) : they have a complete identity(Fig 2) and share nearly 100 AA common, in constant and variable domains respectivly

The Sequence of the concerned gene is  ID: BC030813.1

At last the Protein GenBank  (4) has the following number: AAH30813.1 with 234 amino acids as shown below:

MEAPAQLLFLLLLWLPDTTGEIVMTQSPATLSVSPGERATLSCRASQSVTSNLAWYQQTPGQSPRLVIYGASSRASGVPARFSGSGSGTEFTLTISSLQSEDFAVYYCQQYNKWPHTFGQGTKLDIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQW KVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC

It is shown  in conclusion,  that an invertebrate Echinoderm (Ophuirid Class) IGKappa gene shares entiere identity with a  human immunoglobulin IGK (Fig.2). From now on we have to  think of : Invertebrate Primitive Immunoglobulins about Echinoderms as it is said about  IPA ( Invertebrate Primitive Antibody) (5) also in Echinoderms.

We have not yet the three-dimensional structure of this protein. On the other hand we have the sea star one which is, in a certain  way its “sister”  in  the phylogenic  tree. In fact, compared sequencing of Human IGK and Ophiocomina nigra IGKappa gene present more 90% in similarities as shown in Fig.2.  We have illustrated this work with a supposed anti-HRP “Immunoglobulin” from Ophiocomina nigra (Fig.1), in photon microscopy.

In the present time, we don’t know the evolutionary process which leads from Echinoderms to Man, in matter of Immunoglobulin “ Immunology”. If there is an evolution in this process , many steps are requested to explain such a phenomenon, which suddenly appears ,so:  MHC genes,  CDR1, CDR2, CDR3  regions in the Invertebrate Primitive Antibody (5)

+ We thank greatly  Bo Huang Laboratories

References:

1) Leclerc, M et al (2018) Appl.Biotechnol. Bioeng  5(1): 17-18

2) Leclerc, M (2022) J.Virol. Viral  Dis 2(I)

3) Leclerc,M  et al(2017) Cell and Cellular Life Sc. Vol.2 No1

4) Hutchinson, A.T et al. (2014) Hum.Immunol 75(9):986-90

5) Leclerc, M(2025) Mathews Immunol and Allergy 9(1):36

IGK@ protein [Homo sapiens] graphic (in dark) by NCBI (https://www.ncbi.nlm.nih.gov/protein/AAH30813.1?report=graph) shares IG domains with Ophiocomina nigra IGKappa protein(in grey) issued from ophuirid IGKappa gene

GenBank: AAH30813.1 protein issued from IGK gene has two immunoglobulin domains:

1. Region 1

Region : IgV_L_kappa

Comment : Immunoglobulin (Ig) light chain, kappa type, Variable (V) domain

Location : 22…126

 Common Length 105 aa

1. Region 2

Region : IgC_L

Comment : Immunoglobulin constant domain

Location : 132…231

Common Length 100 aa