The “introns early” hypothesis is the proposal that introns have always been an integral part of the gene.  Genes originated as interrupted structures, and those now without introns have lost them in the course of evolution.

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#Unit 4. Cell Communication and Cell Signaling

T-cell lineage

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#Unit 4. Cell Communication and Cell Signaling

T-Cell Development

1.Commitment

2.antigen receptor gene rearrangements

3.The selection and expansion of cells (β-selection

TLS Online TPP Program

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#Unit 4. Cell Communication and Cell Signaling

The second phase of T-cell development

1.Positive selection: Selection for those cells whose T-cell receptors engage self-MHC.

2.Negative selection: Selection against those cells whose T-cell receptors bind too strongly to self-peptide/MHC combinations.

3.Lineage commitment: Commitment of thymocytes to effector cell lineages, including CD4 helper or CD8 cytotoxic populations

TLS Online TPP Program

#Id: 10292

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 10293

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 10294

#Unit 4. Cell Communication and Cell Signaling