Submitted to: DNA Sequence
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/2001
Publication Date: 8/14/2001
Citation: LONG, E., CAPUCO, A.V., ZHOA, X. MOLECULAR CLONING OF BOVINE EUKARYOTIC TRANSLATION INITIATION FACTOR 4E(EIF-4E) AND ITS EXPRESSION IN BOVINE MAMMARY GLAND AT DIFFERENT PHYSIOLOGICAL STAGES. DNA SEQUENCE. vol. 12, pp. 319-329, 2001. Interpretive Summary: A protein that serves as an important regulator of protein synthesis (translation) in many species was investigated. The bovine gene for this protein, known as eukaryotic translation initiation factor 4E (eIF-4E), was cloned and sequenced. The nucleotide sequence and amino acid sequence of eIF-4E displayed extensive similarity to that in other species. This probably reflects the universal and significant functions that this protei serves in the regulation of protein synthesis. The eIF-4E gene was differentially expressed in the bovine mammary gland at distinct physiological stages. It was expressed at low levels during the prepubertal period of mammary gland growth, but at high levels during lactation. The data imply that eIF-4E may be required for cell differentiation or may stimulate overall protein synthesis to meet the demands of milk production.
Technical Abstract: The eukaryotic translation initiation factor 4E (eIF-4E) regulates proliferation and differentiation of many cell types. Its cDNA has been cloned and sequenced in many species, but not in bovine. Therefore, in the current study, bovine eIF-4E cDNA was cloned and its expression in bovine mammary gland at distinct physiological stages investigated. Bovine eIF-4E cDNA and protein sequences are highly homologous to those from other mammals. Using Northern blot analysis, we did not detect eIF-4E expression in the prepubertal bovine mammary gland, whereas allow level of eIF-4E mRNA was observed in the mammary tissues of heifers during the third estrous cycle. eIF-4E mRNA level is significantly higher (P < 0.01) in the lactating mammary gland compared to the mammary tissues obtained from heifers during the third estrous cycle. Alteration of eIF-4E expression in bovine mammary tissues during different physiological stages indicates the involvement of eIF-4E in mammary development. Elevated eIF-4E expression during lactation may be related to the up-regulation of certain mRNA translation or the acceleration of overall prating synthesis.