Sequence analysis and tissue-specific expression of the B2-microglobulin gene in Aeromonas hydrophila infected Cirrhinus mrigala

Abstract

Partial complementary DNAs of B2-microglobulin genes were cloned from the livers of five species in four genera of Indian carps (Indian InajaI' carp species: Labeo rohita, Catla cat/a, Cirrhinus lnrigala; medium carp: Puntius sarana; minor carp: Labeo hata) subsequent to polymerase chain reaction amplification with self-designed primers derived. froin conserved regions of B2-microglobulin cDNA sequences. The partial B2-microglobulin cDNAs of the five species of carps had sizes from 175 to 206 bp and encoded open reading franles consisting of 58-68 amino acids. The alignment of carp cDNA sequences showed 90.2 to 98.8% homology and that of the deduced amino acid sequences showed 82.7 to 96.50/0 homology. The relationship among the four genera of Indian carps is well correlated with that derived from classic morphologic analyses as showed by a phylogenetic tree constructed of amino acid sequences ofB2-microglobulin cDNAs from carps. The tissue-specific expression of the B2-microglobulin gene was studied in various tissues (liver, kidney, spleen, brain, muscle, testis, heart, intestine, gill and fin) from apparently healthy (control), moribund and survived Cirrhinus lnrigala, experimentally infected with Aerolnonas hydrophila. B2-microglobulin mRNA was detected in all the tissues analyzed irrespective of the bacterial infection.