INTERFERON TAUROLE IN EMBRYO IMPLANTATION

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INTERFERON TAU-ROLE IN EMBRYO IMPLANTATION
Paras Yadav, Jaspreet Singh Arora, Sachinandan
De, Tirtha Kumar Datta, Surender Lal Goswami,
Aarti Bhardwaj, Shalini Jain and Hariom
Yadav Animal Biotechnology, Animal
Biochemistry Division, National Dairy Research
Institute, Karnal-132001, Haryana, India Meerut
Institute of Engeenering and Technology, Meerut,
U.P., India
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EMBRYO MORTALITY30-40 of fertilization are
lost due to embryo demise.Nearly 65 of all
embryonic loss occurs between days 6-18 days of
pregnancyFactors affecting Embryonic death
genotypic factorsNutritional effectsEffects of
energy and proteinConceptus signalRole of
progesteroneInfectious agentsother possible
factors, age breed and affect of male
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Spencer et al., 2004
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Spencer et al., 2004
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Spencer et al.,2004
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Implantation Window
Implantation of the conceptus in domestic farm
species
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Interferon tau

• Interferon tau 172 a.acid protein secreted
• by the trophectoderm of the conceptus
  
  ( Bazer et
  al.,1991)
• Gives the first pregnancy signal (Roberts et
  al.,1999)
• Prevents development of the endometrial
  luteolytic mechanism (Spencer and Bazer,2002)

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Mechanism of action

• Interferon tau suppress estrogen receptor and
  oxytocin (OTR) expression at transcription level
• Oxytocin induces uterine release of luteolytic
  prostaglandin F2alpha pulses
• Prostaglandin F2alpha result in structural and
  functional regression of the ovarian CL
• ( Fleming et al.,2001 )
• 
  
• 
  

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Hypothetical model of IFN-tau stimulated gene
activation and effects on molecules involved in
the PGF2a synthetic pathway
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• Relative changes in circulating hormone levels
  and ovarian changes
• Changes in endometrial hormone response during
  the estrous cycle

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• Relative changes in circulating hormone levels
  during early pregnancy
• Changes in endometrial hormone response during
  early pregnancy

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Transcription of the ER and OTR genes are lower
in pregnantand IFN treated endometrium
( T.H.E.Spencer et
al.,1996 )
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Variants of interferon tau gene

• Multiple gene encodes for IFN-Tau
• Genes are not expressed equivalently
• Variants shows considerable differences in
  biological activity
• 
  (Alan D Eley,1998)
  

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Differences in amounts of mRNA for variants of
ovlFN-r relative to actin mRNA during conceptus
development.

(Alan D Eley,1998)

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In Vitro secretion of IFN-Tau bovine

• Cultured with TCM 199 shows less secretion of IFN
• Cultured with B2 BRL shows high IFN secretion
• Hatched blastocysts shows high secretion of IFN
  than non-hatched ones
• 
  (MiodragStojkovic,1995)

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( Miodrag Stojkovic,1995 )
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• Recombinant interferon tau
• Non glycoslated protein produced in E.coli
• Oestrus cycle synchronized
• Inter-oestrus interval increases up to six days
  due to increase in CL life span
• (
  E.C.L.Bleach et al.,1998 )

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a)Untreated heifers, b) Heifers treated with
rbIFN )