Proteomic analysis of pregnancy-specific serum proteins in buffalo
Abstract
Modern proteomics technique offers an exciting opportunity in solving some of the most
challenging problems of livestock sector, including development of diagnostics for early pregnancy. In
the present study, sera samples obtained at weekly intervals from early pregnant (Day 0 to Day 42
post-AI) buffaloes, and on days 0, 7 and 14 from non-pregnant cyclic buffaloes, were subjected to
depletion of high abundant proteins followed by 2-dimensional gel electrophoresis and densitometric
analysis, which revealed the presence of at least 65 2-D gel spots exhibiting up-regulation,
down-regulation or specific appearance at a specific stage during early buffalo pregnancy, except for
the spots correlating with the high abundant proteins’ location. Comparison with ExPASy and NCBI
databases matched 48 of these spots with known proteins, but with varying degrees of confidence in
terms of Mascot score and the species. Although high abundant proteins were depleted before 2-D
electrophoresis, yet in some of the picked spots isoforms of common abundant proteins viz. Serum
Albumin, IgG, Serrotransferrin, Complement and MHC molecules, were found. Some of these
identified spots appear promising pregnancy bio-markers, especially synaptojanin-1, apolipoprotein
A-1, apolipoprotein B, Keratin 10 and Von Willebrand factors, which are documented to have role in
embryogenesis and early pregnancy. Gene ontology based functional analysis of the identified proteins
suggested that most of these were involved in regulatory, catalytic, cell differentiation and transporter
functions. Involvement of identified proteins in 23 pathways, including the embryogenesis specific Wnt
signalling pathway, confirms the essentiality of these proteins in early pregnancy. The result on the
protein-protein interaction data from current experiment, described by network of 9 proteins,
strengthens our belief that the significantly affected early pregnancy associated proteins are closely
related. Considering that proteomics in animal research is still in its infancy, it is a long way before
practical applications of such experiments could actually be realized.
Description
Keywords
Proteomics, 2-D electrophoresis, MS, Early pregnancy