Exam 5 Molecular Biology Questions
With Complete Solutions
Genetically modified organism (GMO) - AnswerAny microorganism, plant, or animal in
which genetic engineering techniques have been used to introduce, remove, or modify
specific parts of its genome.
/.Genetically modified animals - Answer-Study gene function and regulation
-Lab animals manipulated to exhibit human diseases
-Understand and cure genetic diseases
-Generate new organisms for other fields of research
/.Genetically modified plants - Answer-GMO's show great promise in improving
agriculture:
-plants could be engineered to better tolerate temperatures or weather extremes, to
contain various vitamins, etc
-GM food have potential to end world hunger but there are fears that the disease or pest
resistant genes inserted into crop plants might escape into other plants, creating hard to
control super weeds.
/.Transgenic organism - AnswerCarries transferred genetic material (the transgene) that
has been inserted into its genome at a random site.
/.Knockout organism - AnswerCreated by gene targeting - the replacement or mutation
of a particular gene.
/.Cloned organism - AnswerA genetically identical organism produced by nuclear
transfer from adult somatic (body) cells to an unfertilized egg.
/.Laboratory mouse model - Answer-Small
-hardy
-short life cycle
-genetics possible
-many useful strains and tools
/.Transgenic mice - Answer1) 1980 - the first transgenic mouse was produced by
microinjection of foreign DNA into fertilized eggs.
2) 1982- "Super" mice expressing rat growth hormone gene coding sequence.
/.Transgenic mice: How to make - Answer1. Microinjection of DNA into the pronucleus
of a fertilized mouse egg
2. Implantation of the microinjected embryo into a foster mother
3. Analysis of mouse pups and subsequent generations for the stable integration and
expression of the transgene
, /.Pronuclear injection - Answer- Transgene: Minimal requirements for expression of
DNA?
--Promoter; gene (cDNA), polyA signal
-Critical window of time before pronuclei fuse to form a diploid zygotic nucleus. Foregin
DNA should be integrated into the genome prior to the doubling. Usually inject sperm
pronucleus since it is larger and closer to the egg surface.
/.Analysis of stable integration - AnswerTwo important questions:
1) Is there stable integration of the transgene into the mouse chromosome?
2) If the transgene is present, is it expressed appropriately?
-Success rate is 2.5-6% in mice
Tail Biopsies: DNA analysis by southern blot or PCR.
-Integration is random and occurs by non homologous recombination
-More than one copy may be integrated
/.Analysis of transgene expression at level of transcription - AnswerUse:
-Northern Blot
-RT-PCR
-In situ hybridization, etc
/.Analysis of transgene expression at level of translation - AnswerUse:
-Western blot
-Immunohistochemistry
-GFP expression, etc
/.Inducible transgenic mice - AnswerWhat can be done if the transgenic is embryonic
lethal?
-Inducible Tet-Off system
/.Tet inducible system (tet-on) - AnswerSeveral mutations are introduced into the tTA so
that this transactivator binds the TRE in the presence of Dox or Tet.
/.Tet inducible system (tet-off) - AnswerTet responsive transcriptional activator (tTA): a
chimeric protein of EColi Tet-controlled repressor (tetR) and VP16 transactivation
domain.
-tTA binds the Tet-response element (TRE) upstream of the minimal MV promoter in the
absence of Tetracyclin (Tet) or Doxycycline (Dox).
/.Gene targeted mouse models - AnswerThe ability to create a mouse of any desired
genotype.
- A US based consortium is systematically knocking out mouse genes one by one in
embryonic stem cells.
-A European based consortium is engineering knockout cells containing genes that can
be switched on or off at any stage of development in the mutant mouse.
With Complete Solutions
Genetically modified organism (GMO) - AnswerAny microorganism, plant, or animal in
which genetic engineering techniques have been used to introduce, remove, or modify
specific parts of its genome.
/.Genetically modified animals - Answer-Study gene function and regulation
-Lab animals manipulated to exhibit human diseases
-Understand and cure genetic diseases
-Generate new organisms for other fields of research
/.Genetically modified plants - Answer-GMO's show great promise in improving
agriculture:
-plants could be engineered to better tolerate temperatures or weather extremes, to
contain various vitamins, etc
-GM food have potential to end world hunger but there are fears that the disease or pest
resistant genes inserted into crop plants might escape into other plants, creating hard to
control super weeds.
/.Transgenic organism - AnswerCarries transferred genetic material (the transgene) that
has been inserted into its genome at a random site.
/.Knockout organism - AnswerCreated by gene targeting - the replacement or mutation
of a particular gene.
/.Cloned organism - AnswerA genetically identical organism produced by nuclear
transfer from adult somatic (body) cells to an unfertilized egg.
/.Laboratory mouse model - Answer-Small
-hardy
-short life cycle
-genetics possible
-many useful strains and tools
/.Transgenic mice - Answer1) 1980 - the first transgenic mouse was produced by
microinjection of foreign DNA into fertilized eggs.
2) 1982- "Super" mice expressing rat growth hormone gene coding sequence.
/.Transgenic mice: How to make - Answer1. Microinjection of DNA into the pronucleus
of a fertilized mouse egg
2. Implantation of the microinjected embryo into a foster mother
3. Analysis of mouse pups and subsequent generations for the stable integration and
expression of the transgene
, /.Pronuclear injection - Answer- Transgene: Minimal requirements for expression of
DNA?
--Promoter; gene (cDNA), polyA signal
-Critical window of time before pronuclei fuse to form a diploid zygotic nucleus. Foregin
DNA should be integrated into the genome prior to the doubling. Usually inject sperm
pronucleus since it is larger and closer to the egg surface.
/.Analysis of stable integration - AnswerTwo important questions:
1) Is there stable integration of the transgene into the mouse chromosome?
2) If the transgene is present, is it expressed appropriately?
-Success rate is 2.5-6% in mice
Tail Biopsies: DNA analysis by southern blot or PCR.
-Integration is random and occurs by non homologous recombination
-More than one copy may be integrated
/.Analysis of transgene expression at level of transcription - AnswerUse:
-Northern Blot
-RT-PCR
-In situ hybridization, etc
/.Analysis of transgene expression at level of translation - AnswerUse:
-Western blot
-Immunohistochemistry
-GFP expression, etc
/.Inducible transgenic mice - AnswerWhat can be done if the transgenic is embryonic
lethal?
-Inducible Tet-Off system
/.Tet inducible system (tet-on) - AnswerSeveral mutations are introduced into the tTA so
that this transactivator binds the TRE in the presence of Dox or Tet.
/.Tet inducible system (tet-off) - AnswerTet responsive transcriptional activator (tTA): a
chimeric protein of EColi Tet-controlled repressor (tetR) and VP16 transactivation
domain.
-tTA binds the Tet-response element (TRE) upstream of the minimal MV promoter in the
absence of Tetracyclin (Tet) or Doxycycline (Dox).
/.Gene targeted mouse models - AnswerThe ability to create a mouse of any desired
genotype.
- A US based consortium is systematically knocking out mouse genes one by one in
embryonic stem cells.
-A European based consortium is engineering knockout cells containing genes that can
be switched on or off at any stage of development in the mutant mouse.
