1) Interactomics is the study of interactions between genes or proteins, including genetic and physical interactions. 2) Complementation groups can identify mutations in the same or different genes involved in the same pathway through genetic crosses of mutant organisms. 3) Modifier screens uncover new genes involved in a biological pathway by identifying mutations that alter the phenotype of an original mutant. Mapping protein-protein interaction networks provides a framework for understanding biology as an integrated system.

1. Interactome and Its Influence on
Various Fields of Biology
BY SREEREMYA.S
FACULTY OF BIOLOGY

2. • INTRODUCTION In interactome, basically for interaction of proteins
there is certain key elements requited, they are: Interactomics and
Proteomics, Complementation groups, Modifier screens 1.
Interactomics and Proteomics
• Field of interactomics is concerned with interactions between genes
or proteins. They can be genetic interactions, in which two genes
are mainly involved in the same functional pathway (leading to a
particular phenotype), or physical interactions, in which there is
direct physical contact between two proteins (or between protein
and DNA) (Janga et al.,2008). 2. Complementation groups Using
forward saturation genetics, one may recover several independent
mutants with the same (or similar) phenotype (Hernández et al.,
2007). There are two possibilities: a) Mutations are in the same
gene b) Mutations are in different genes involved in the same
pathway. Scenario

3. • (b) Can be tested genetically with a complementation test:
• Cross two homozygous mutants (samples) and observe heterozygous
offspring phenotypes(samples)
• Mutations in the same gene will not complement
• offspring have mutant phenotype
• Mutations in different genes will complement
• offspring have wild
• Type phenotype
• Do pairwise crosses for all mutants to identify complementation groups
• Typically each complementation group represents a different gene
• If many mutations are recovered in the same genes, this implies
saturation

4. • Modifier screens
• This is one and prime way to find new genes involved in the pathway leading to a
mutant phenotype. It can also identify epistatic interactions. Forward saturation
mutagenesis is usually performed in the background of a particular mutant
phenotype, then new mutants that alter the phenotype of the original mutant are
identified. Types of mutations that can be uncovered (Jeong, 2001):
• Back mutations
• A second mutation in the same gene that corrects the previous mutation and
restores phenotype to wild Type This is rare; modifying mutations are typically in
other genes. Enhancers Mutations that make the original mutant phenotype more
extreme Suppressors Mutations that make the original mutant phenotype less
extreme PROTEIN-PROTEIN INTERACTIONS
• Protein – protein interactions are fundamental for all biological processes, and a
comprehensive delineation of of all protein – protein interactions that can take
place in an organism provides a framework for understanding biology as an
integrated system (Jonsson et al.,2006).

5. • SYSTEMATIC MAPPING OF INTERACTOMENETWORKS
• Most gene products mediate their function within
ramified and complex networks of interconnected
macromolecules. Studies in model organisms suggest
that complex macromolecular networks have
topological and dynamic properties that reflect
biological phenomena. Thus, an understanding of
biological mechanisms and disease processes mainly
communicable disease demands a ‘systems’ approach
that goes beyond one-at-a-time studies of single
components to more global analyses of the structure,
function and dynamics of the networks in which
macromolecules function (Kerrien et al.,2007).

6. • The full interactome network as the complete
collection of all physical protein–protein
interactions that can take place within a single
cell. Construction of comprehensive sets of
protein–protein interactions, interactomes,
requires the creation of genome-scale resource
collections of open reading frames (ORFeomes)
cloned so as to facilitate protein expression,
generated iteratively based on improved gene
predictions and experimental verification and
capturing all expressed iso forms (splice variants
and polymorphisms)(Kitano,2007).

7. • ORFeomes, as trustful indications of the encoded
proteome, provide the starting material for
carrying out high-throughput interaction studies
that are then validated by orthogonal interaction
methods(Lehner et al.,2004). The resulting
interactome maps are regarded as ‘framework’
information; and by integrating other functional
genomic and proteomic data sets, increasingly
detailed and reliable biological models can be
generated(Lage et al.,2007)

8. • Current estimates for the complete yeast interactome suggest, 29
000 potential protein interactions, on the basis of experimental and
computational analyses along with incorporating literature-curated
interactions such as those collected in the MIPS databases. So far,
the worm and fly interactome maps each contain
approximately5000 high-quality putative interactions derived
primarily from high-throughput yeast two-hybrid (Y2H) screens.
These two data sets basically demonstrate the feasibility of
interactome mapping projects for metazoans, and they also
illustrate the power of merging multiple approaches to model
biological networks (Maxwell et al., 2007). However, to fully
understand human biology and the molecular mechanisms
underlying diseases such as cancer, systematic experimental
mapping of the human interactome itself is necessary(Ma-Lauer et
al.,2012).

9. • Although completed genome sequences
provide lists of tens of thousands of predicted
unique proteins (26 000 for the human
proteome, disregarding splice variants and
post-translational modifications), the
sequences by themselves do not cater proper
understanding of the underlying principles of
cellular systems(Uetzet al.,2000). Proteome-
scale information is also required at structural,
functional and dynamic levels.

10. • This information should comprise various molecular
networks, such as regulatory, biochemical or protein–
protein interaction networks(Nyfeler et al.,2005).The initial
challenge is the generation of comprehensive network
maps, basically represented as nodes (e.g. proteins, RNAs,
DNA binding sites or metabolites) linked by edges
corresponding to molecular interactions (e.g. protein–
protein interactions, enzymatic reactions, DNA–protein,
etc.)(Barrios-Rodiles et al.,2005).For each network map,
individual nodes and edges need to be perturbed
systematically to help in understanding the main logic of
molecular networks involved in any biological processes of
interest(Bailer et al.,2009).

11. REFERNCE
• S.Sreeremya,2018 Interactome and Its
Influence on Various Fields of Biology, Journal
of Research in Biotechnology, Pharmaceutical
Technology and Management Volume 1 Issue
1