Gene structure and comparative and phylogenetic analyses of Catla catla CYP1A full-length cDNA and its responsiveness to enzo(a)pyrene and copper sulphate at early developmental stages

Abstract

In the present study, full-length CYP1AcDNA from Catla catla (Catla) has been identified,and its real-time quantitative reverse transcription PCR(qRT-PCR) expression has been evaluated in differenttissues, developmental stages (0, 3, 6, 12 and 24 h and 5,7 and 9 days post-fertilization) and copper sulphate andbenzo(a)pyrene (BaP)-treated 5-day post-fertilization(dpf) larvae (6 to 6.5 mm). Various structural, compar-ative and phylogenetic analyses of the deduced aminoacid sequence revealed that the identified gene of Catlabelongs to the CYP1A1 subfamily. Among differenttissues of Catla, the highest CYP1A expression wasobserved in the kidney followed by the liver, muscle,gill, intestine and brain. CYP1A mRNA expression wasdetected during all the larval developmental stages,including the unfertilized egg with the highest expres-sion on 9 dpf. BaP (3.5 ppb) and copper sulphate (sub-lethal dose 0.516 ppm) challenge test for 96 h to Catlalarvae revealed the highest CYP1A1 expression at 48 hpost-challenge. CYP1A1 transcript also showed aconcentration-dependent increase in expression follow-ing exposure at 1.75 and 3.5 ppb of BaP for 48 h. Itsexpression profiling indicates that it is functional at earlydevelopmental stages. It can also be used to develop aspecific biomarker tool for monitoring environmental pollution.