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Locus description: Channel catfish (Ictalurus punctatus) IGH

DNA

Channel catfish IGH locus

The Channel catfish (Ictalurus punctatus) IGH locus spans probably between 750 and 1000 kb. It is organized in two clusters which are in the same transcriptional orientation [1,2].
The 5' cluster [2] consists of multiple IGHV genes belonging to seven subgroups, one IGHV-D-J rearranged gene, one germline IGHJ gene, and three IGHC genes, the IGHM3 and IGHM2 pseudogenes, and the functional IGHD2 gene [7,10].
The 3' cluster [1] consists of multiple IGHV genes belonging to seven subgroups [8,9], three functional IGHD genes [3], nine functional IGHJ genes [4,5] and two IGHC genes [6,7], localized 2 kb downstream from the IGHJ genes and comprising the functional IGHM1 and IGHD1 genes [6].

Clusters

The IGHV genes of the 5' cluster are located upstream from IGHM3 but extends no further than 270 kb [2]. One IGHV-D-J rearranged gene is located 400 bp upstream from IGHJ11 gene, itself 1.2 kb upstream of IGHM3 CH1 exon.
The IGHV genes of the 3' cluster are widely dispersed within a 725 kb region that extends from IGHM3 to IGHM1 [8,9]. The 3 IGHD genes are within a 7.4 kb region [3], 8.6 kb upstream from the IGHJ genes and at an unknown distance downstream of the IGHV genes. The IGHJ genes are within a 2.2 kb region [4,5], 2 kb upstream the IGHM1 CH1 exon.

NOMENCLATURE

IGHV gene nomenclature

Channel catfish (Ictalurus punctatus) IGHV genes are designated by a number for the subgroup, following by the letter S and a number

IGHD group gene nomenclature

Channel catfish (Ictalurus punctatus) IGHD group genes of the 5' and 3' clusters are designated with the number 2 and 1, respectively for the cluster, followed by a hyphen and a gene number.

REFERENCES
[1] Ventura-Holman, T. and Lobb, C.J., Mol. Immunol., 38, 557-564 (2001).

[2] Ghaffari, S.H. and Lobb, C.J., J. Immunol., 162, 1519-1529 (1999).

[3] Hayman, J.R. and Lobb, C.J., J. Immunol., 164, 1916-1924 (2000).

[4] Hayman, J.R. et al., J. Immunol., 151, 3587-3596 (1993).

[5] Ghaffari, S.H. and Lobb C.J., Mol. Immunol., 29, 151-159 (1992).

[6] Magor, B.G. et al., J. Immunol., 153, 5556-5563 (1994).

[7] Bengten, E. et al., Unpublished (2001).

[8] Ventura-Holman, T. et al., Mol. Immunol., 31, 823-832 (1994).

[9] Ventura-Holman, T. et al., Eur. J. Immunogenet., 23, 7-14 (1996).

[10] Warr, G., Personnal communication (13/06/2002).

Created: 23/07/2002
Authors: Nathalie Bosc

[1]	Ventura-Holman, T. and Lobb, C.J., Mol. Immunol., 38, 557-564 (2001).
[2]	Ghaffari, S.H. and Lobb, C.J., J. Immunol., 162, 1519-1529 (1999).
[3]	Hayman, J.R. and Lobb, C.J., J. Immunol., 164, 1916-1924 (2000).
[4]	Hayman, J.R. et al., J. Immunol., 151, 3587-3596 (1993).
[5]	Ghaffari, S.H. and Lobb C.J., Mol. Immunol., 29, 151-159 (1992).
[6]	Magor, B.G. et al., J. Immunol., 153, 5556-5563 (1994).
[7]	Bengten, E. et al., Unpublished (2001).
[8]	Ventura-Holman, T. et al., Mol. Immunol., 31, 823-832 (1994).
[9]	Ventura-Holman, T. et al., Eur. J. Immunogenet., 23, 7-14 (1996).
[10]	Warr, G., Personnal communication (13/06/2002).