DIGE based proteome analysis of mammary gland tissue in water buffalo (Bubalus bubalis): Lactating vis-a-vis heifer Manoj K. Jena a , Jagadeesh Janjanam a, 1 , Jasmine Naru b , Saravanan Kumar d , Sudarshan Kumar a , Surender Singh a , Sushil K. Mohapatra a , Srujana Kola c , Vijay Anand a , Shalini Jaswal a , Arvind K. Verma a , Dhruba Malakar a , Ajay K. Dang a , Jai K. Kaushik a , Vanga S. Reddy d , Ashok K. Mohanty a, ⁎ a National Dairy Research Institute (NDRI), Karnal 132001, India b Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India c Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110016, India d International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India ARTICLE INFO ABSTRACT Article history: Received 21 June 2014 Accepted 20 January 2015 Mammary gland is an exocrine and sebaceous gland made up of branching network of ducts that end in alveoli. Milk is synthesized in the alveoli and secreted into alveolar lumen. Mammary gland represents an ideal system for the study of organogenesis that undergoes successive cycles of pregnancy, lactation and involution. To gain insights on the molecular events that take place in pubertal and lactating mammary gland, we have identified 43 differentially expressed proteins in mammary tissue of heifer (non-lactating representing a virgin mammary gland), and lactating buffaloes (Bubalus bubalis) by 2D-difference gel electrophoresis (2D-DIGE) and mass spectrometry. Twenty one proteins were upregulated during lactation whereas 8 proteins were upregulated in heifer mammary gland significantly (p<0.05). Bioinformatics analyses of the identified proteins showed that a majority of the proteins are involved in metabolic processes. The differentially expressed proteins were validated by real-time PCR and Western blotting. We observed differential expressions of certain new proteins including EEF1D, HSPA5, HSPD1 and PRDX6 during lactation which have not been reported before. The differentially expressed proteins were mapped to available biological pathways and networks involved in lactation. This study signifies the importance of some proteins which are preferentially expressed during lactation and in heifer mammary gland. Biological significance This work is important because we have generated information in water buffalo (B. bubalis) for the first time which is the major milk producing animal in Indian Subcontinent. Out of a present production of 133 million tons of milk produced in India, contribution of buffalo milk is around 54%. Its physiology is somewhat different from the lactating cows. Buffalo milk composition varies from cow milk in terms of higher fat and total solid content, which Keywords: Mammary gland 2D-DIGE Heifer Buffalo Lactation JOURNAL OF PROTEOMICS 119 (2015) 100 – 111 ⁎ Corresponding author. Tel.: +91 184 2259538; fax: +91 184 2250042. E-mail address: ashokmohanty1@gmail.com (A.K. Mohanty). 1 Present Address: Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA. http://dx.doi.org/10.1016/j.jprot.2015.01.018 1874-3919/© 2015 Elsevier B.V. All rights reserved. Available online at www.sciencedirect.com ScienceDirect www.elsevier.com/locate/jprot