1 / 20

Phage Strategies for Regulatory Region Control

Explore the intricate regulatory mechanisms of phage genomes, from establishment of lysogeny to the lytic cycle. Learn about key components like promoters, terminators, and regulators in gene expression control.

efia
Download Presentation

Phage Strategies for Regulatory Region Control

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Phage Strategies Timothy G. Standish, Ph. D.

  2. The l Regulatory Region tR1 tL nutL nutR N cI cro cIII cII Terminator left N utilization left N utilization right Terminator right Positive regulator Anti-terminator Repressor Anti-repressor Positive regulator “c” = clear referring to the clear plaques resulting from functional c genes

  3. The l Regulatory Region PRM PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro cIII cII Promoter Represser Establish-ment Promoter/ Operator left Promoter Represser Maintainence Promoter/ Operator right Positive regulator Anti-terminator Repressor Anti-repressor Positive regulator “c” = clear referring to the clear plaques resulting from functional c genes

  4. The l Regulatory Region:Infection PRM PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro STOP STOP cIII cII Transcription Transcription Transcription Transcription Host RNA Polymerase recognizes PL and PR and begins transcription of the N and cro proteins

  5. The l Regulatory Region:Infection - Establishment of Lysogeny PRM PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro cIII cII pN Host RNA Polymerase recognizes PL and PR and begins transcription of the N and cro proteins As they are the very first genes to be expressed, N and cro are called “immediate early” genes. cro

  6. The l Regulatory Region:Infection - Establishment of Lysogeny PRM PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro cIII cII pN pN binds to nut sites allowing transcription through tR1 and tL cro

  7. The l Regulatory Region:Infection - Establishment of Lysogeny PRm PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro pN pN cIII cII Transcription Transcription pN binds to nut sites allowing transcription through tR1 and tL cro

  8. The l Regulatory Region:Infection - Establishment of Lysogeny PRm PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro pN pN cIII cII cII cII cIII cIII The cII and cIII proteins are produced. In vivo a protein called HflA rapidly breaks down cII unless it is combined with cIII. cII up regulates transcription from PRE. cro

  9. The l Regulatory Region:Infection - Establishment of Lysogeny PRm PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro pN pN cIII cII Transcription cII cIII Transcription from PRE makes mRNA complementary to the cro mRNA thus inhibiting cro translation cro

  10. The l Regulatory Region:Infection - Establishment of Lysogeny PRm PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro pN pN cIII cII Transcription cII cIII The transcript from PRE provides a 3’ untranslated region with an efficient ribosome binding site before the start of the cI gene, thus cI repressor is efficiently produced.

  11. The l Regulatory Region:Infection - Establishment of Lysogeny PRm PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro pN cI cI pN cIII cII cII cIII cI The repressor gene product of cI binds to OR and OL preventing transcription from PR and PL.

  12. The l Regulatory Region:Infection - Establishment of Lysogeny PRM PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro cIII cII Transcription The repressor up-regulates expression from PRM maintaining repressor production and preventing expression of any other proteins and establishing lysogeny. cI cI

  13. The l Repressor Protein Repressor Repressor dimer C C C N N N • Repressor protein has two functional domains: • An amino acid (residue) 1-92 N-terminal DNA binding domain which binds to OR and OL • A C-terminal protein binding domain essential for dimerization running from amino acids 132-236 • A 40 residue connector runs Between the two domains Repressor only binds DNA efficiently when it is a dimer

  14. The l Regulatory Region:Infection - Establishment of The Lytic Cycle PRM PRE PL/OL OR/PR tR1 tL nutL nutR N cI cro cIII cII pN Host RNA Polymerase recognizes PL and PR and begins transcription of the N and cro proteins As they are the very first genes to be expressed, N and cro are called “immediate early” genes. cro

  15. The l Regulatory Region:Infection - Establishment of The Lytic Cycle OR/PR PRM Host RNA Polymerase recognizes PL and PR and begins transcription of the N and cro proteins cI cro

  16. The l Regulatory Region:Infection - Establishment of The Lytic Cycle OR/PR PRM OR3 OR2 OR1 Host RNA Polymerase recognizes PL and PR and begins transcription of the N and cro proteins 5’CAT’ACGTTAAATCTATCACCGCAAGGGATAAATATCTAACACCGTGCGTGTTGACTATTTTACCTCTGGCGGTGATAATGGTTGC’ATG3’ 3’ATG’TGCAATTTAGATAGTGGCGTTCCCTATTTATAGATTGTGGCACGCACAACTGATAAAATGGAGACCGCCACTATTACCAACG’TAC5’ cI cro

  17. C C C The l Regulatory Region:Infection - Establishment of The Lytic Cycle N N N OR3 OR2 OR1 5’CAT’ACGTTAAATCTATCACCGCAAGGGATAAATATCTAACACCGTGCGTGTTGACTATTTTACCTCTGGCGGTGATAATGGTTGC’ATG3’ 3’ATG’TGCAATTTAGATAGTGGCGTTCCCTATTTATAGATTGTGGCACGCACAACTGATAAAATGGAGACCGCCACTATTACCAACG’TAC5’ cI cro The N terminus of the repressor binds to OR1 and 2 with high affinity The N terminus of the repressor binds to OR1 and 2 with high affinity The N terminus of the repressor binds to OR1 and 2 with high affinity

  18. The l Regulatory Region:Infection - Establishment of The Lytic Cycle RNA Polymerase RNA Polymerase OR3 OR2 OR1 Host RNA Polymerase recognizes PL and PR and begins transcription of the N and cro proteins 5’CAT’ACGTTAAATCTATCACCGCAAGGGATAAATATCTAACACCGTGCGTGTTGACTATTTTACCTCTGGCGGTGATAATGGTTGC’ATG3’ 3’ATG’TGCAATTTAGATAGTGGCGTTCCCTATTTATAGATTGTGGCACGCACAACTGATAAAATGGAGACCGCCACTATTACCAACG’TAC5’ cI cro

  19. The l Regulatory Region:Infection - Establishment of The Lytic Cycle OR3 CTATCACCGCAAGGGATAA OR2 CTAACACCGTGCGTGTTGA OR1 TTACCTCTGGCGGTGATAA OL3 TAACCATCTGCGGTGATAA OL2 TTATCTCTGGCGGTGTTGA OL1 ATACCACTGGCGGTGATAC OR3 CTATCACCGCAAGGGATAA OR2 CTAACACCGTGCGTGTTGA OR1 TTACCTCTGGCGGTGATAA OL3 TAACCATCTGCGGTGATAA OL2 TTATCTCTGGCGGTGTTGA OL1 ATACCACTGGCGGTGATAC CON -TAYCWCYGGCGGTGWTR- Right and left operator sites share a common consensus sequence.

  20. The End

More Related