Adaptive Evolution of Gene Expression in Antarctic Fishes: Divergent Transcription of the 5�-to-5 � Linked Adult �1- and �-Globin Genes of the Antarctic Teleost Notothenia coriiceps is Controlled by Dual Promoters and

• Main Authors: Intergenic Enhancers, David T. Lau, Amna Saeed-kothe, Sandra K. Parker, H. William Detrich
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; New Zealand; Southern Ocean; The Antarctic; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.327.6928; http://icb.oxfordjournals.org/content/41/1/113.full.pdf

SYNOPSIS. Unlike temperate fishes, Antarctic fishes of the notothenioid suborder, whose body temperatures (�2 to �1�C) conform to the Southern Ocean, must express their genomes in an extremely cold thermal regime. To determine whether these fishes have evolved compensatory adjustments that maintain efficient gene transcription at low temperatures, we have initiated studies of the cis-acting regulatory elements that control globin gene expression in the Antarctic rockcod Notothenia coriiceps and in its close relative, the temperate New Zealand black cod N. angustata (habitat temperature ��6to�15�C). The genes encoding the major �1 and � globins of these fishes are tightly linked in head-to-head (5 � to 5�) orientation. The intergenic regions separating the globin genes in the two fishes, �4.3 kb in N. coriiceps and �3.2 kb in N. angustata, are highly similar in sequence, the major difference being the absence of a 1.1-kb, repeat-containing segment in the latter. To assess the promoter and enhancer activities of the intergenic regions, each was cloned into the luciferase-reporter vector pGL3-Basic, and the constructs were transfected into MEL cells. Upon DMSO induction of MEL cell differentiation