آنچه هستی ، هدیه خداوند است به تو
و
آنچه میشوی ،هدیه توست به خداوند
پس
بی نظیر باش ، زیرا بی نظیر آفریده شده ای
دانشگاه آزاد اسلامی
گروه زیست شناسی
استاد : سرکار خانم دکترمحمودی
تحقیق توسط : نرگس آرین جاه
زیست تکوینی جانوری
The initial stages of development depend on m-rna and proteins accumulated in the oocyte , and during these stages , certain genes are essential for fertilization , first cleavage and embryonic genome activation .
The aim of this study was first to search for avian oocyt – specific genes
The activation of molecular pathways underlying oocyte to embryo transition (oet) depends exclusively on maternal Rnas and proteins accumulated during growth of the oocyte .
Indeed,by the two cell stage , the major pathways regulated by maternal mrna are targeted protein degradation, translational control and chromatin remodelling .
The recruitment of maternal mrna for translation has long been recognized as a widespread mechanism to generate newly synthesized proteins in maturing oocytes and fertilized eggs .
Conversely,rna that is not larger needed in the early embryo.
moreover, careful regulation of proteolysis during the same period is likely to be important in oocytes, which are prodominantly transcriptionally inactive and must often wait for long periods before fertilization in different species.
Maternal transcripts that are present in the early pre-implantation embryo can be subdivided into two classes according to whether they are synthesized soon after embryonic genome activation or not.
The firstis common to the oocyte and early embryo and is replenished after activation of the zygotic genome. The second consists of oocyte-specific mrna that is not subeqently transcribed from zygotic genes in the embryo this class of mrna may be detrimental to early post-fertilization development.
Birds represent a good model to observe progressive accumulation of mrna in the oocyte befor ovulation. The embryonic genome of a model bird(the chicken), is activated when the embryo contains 30000-50000 cells 24h after fertilization.
Protein and mrna, accumulated as the chicken oocyte matures,are essential not only for fertilization and first cleavage but also for supporting a high number of emberyonic cell divisions before genome activation.
The avian oocyte consists of a large amount af yolk and a structure called the germinal disc(gd). The gd is a white plaque of about 3-4mm diameter an the top of the oocyte. It contaions the nucleus and 99% of oocyte organelles althoughit occupies less than 1% of the cell volume.
و
آنچه میشوی ،هدیه توست به خداوند
پس
بی نظیر باش ، زیرا بی نظیر آفریده شده ای
دانشگاه آزاد اسلامی
گروه زیست شناسی
استاد : سرکار خانم دکترمحمودی
تحقیق توسط : نرگس آرین جاه
زیست تکوینی جانوری
The initial stages of development depend on m-rna and proteins accumulated in the oocyte , and during these stages , certain genes are essential for fertilization , first cleavage and embryonic genome activation .
The aim of this study was first to search for avian oocyt – specific genes
The activation of molecular pathways underlying oocyte to embryo transition (oet) depends exclusively on maternal Rnas and proteins accumulated during growth of the oocyte .
Indeed,by the two cell stage , the major pathways regulated by maternal mrna are targeted protein degradation, translational control and chromatin remodelling .
The recruitment of maternal mrna for translation has long been recognized as a widespread mechanism to generate newly synthesized proteins in maturing oocytes and fertilized eggs .
Conversely,rna that is not larger needed in the early embryo.
moreover, careful regulation of proteolysis during the same period is likely to be important in oocytes, which are prodominantly transcriptionally inactive and must often wait for long periods before fertilization in different species.
Maternal transcripts that are present in the early pre-implantation embryo can be subdivided into two classes according to whether they are synthesized soon after embryonic genome activation or not.
The firstis common to the oocyte and early embryo and is replenished after activation of the zygotic genome. The second consists of oocyte-specific mrna that is not subeqently transcribed from zygotic genes in the embryo this class of mrna may be detrimental to early post-fertilization development.
Birds represent a good model to observe progressive accumulation of mrna in the oocyte befor ovulation. The embryonic genome of a model bird(the chicken), is activated when the embryo contains 30000-50000 cells 24h after fertilization.
Protein and mrna, accumulated as the chicken oocyte matures,are essential not only for fertilization and first cleavage but also for supporting a high number of emberyonic cell divisions before genome activation.
The avian oocyte consists of a large amount af yolk and a structure called the germinal disc(gd). The gd is a white plaque of about 3-4mm diameter an the top of the oocyte. It contaions the nucleus and 99% of oocyte organelles althoughit occupies less than 1% of the cell volume.
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