Leah McPhillips
@leahmcphillips.bsky.social
Microbiology PhD student in Tung Le’s lab at the John Innes Centre - interested in all things Streptomyces and plasmid related 🔬🧫 She/Her
Yay huge congrats Tom and everyone involved!
December 16, 2025 at 9:08 AM
Yay huge congrats Tom and everyone involved!
🧵 7/7 Despite this, both SCP1 ParBs behave like canonical CTPase ParBs, and have exquisite DNA-binding specificity for their parS sites, highlighting how these systems can coexist on one plasmid. But, when put to the test, only the ParB1 protein, not the ParB2 protein, contributed to SCP1 stability.
December 11, 2025 at 1:33 PM
🧵 7/7 Despite this, both SCP1 ParBs behave like canonical CTPase ParBs, and have exquisite DNA-binding specificity for their parS sites, highlighting how these systems can coexist on one plasmid. But, when put to the test, only the ParB1 protein, not the ParB2 protein, contributed to SCP1 stability.
🧵 6/7 However, the SCP1 ParBs had less conserved CTPase domains, suggesting they may deviate in their ability to bind/hydrolyse CTP. Are both the SCP1 ParBs bona fide ParB partitioning proteins? And moreover, do they actually play a role in maintaining SCP1 in its multicellular Streptomyces host?!
December 11, 2025 at 1:33 PM
🧵 6/7 However, the SCP1 ParBs had less conserved CTPase domains, suggesting they may deviate in their ability to bind/hydrolyse CTP. Are both the SCP1 ParBs bona fide ParB partitioning proteins? And moreover, do they actually play a role in maintaining SCP1 in its multicellular Streptomyces host?!
🧵 5/7 Enter SCP1! It’s a fascinating plasmid for many reasons. Historically, it’s been so important for our understanding of Streptomyces genetics, it encodes an antibiotic biosynthetic gene cluster, it’s linear, but most interestingly of all, it has not one but two type I HTH-ParB systems.
December 11, 2025 at 1:32 PM
🧵 5/7 Enter SCP1! It’s a fascinating plasmid for many reasons. Historically, it’s been so important for our understanding of Streptomyces genetics, it encodes an antibiotic biosynthetic gene cluster, it’s linear, but most interestingly of all, it has not one but two type I HTH-ParB systems.
🧵 4/7 The most common combo was two type I HTH-ParB systems. These systems have a CTP-dependent molecular switch, ParB, which binds CTP through a highly conserved CTPase domain. To investigate how two type I HTH-ParB systems can coexist on a single plasmid, we needed a plasmid to study!
December 11, 2025 at 1:31 PM
🧵 4/7 The most common combo was two type I HTH-ParB systems. These systems have a CTP-dependent molecular switch, ParB, which binds CTP through a highly conserved CTPase domain. To investigate how two type I HTH-ParB systems can coexist on a single plasmid, we needed a plasmid to study!
🧵 3/7 We set out to identify diverse plasmids encoding partition systems and found many plasmids didn’t just have one system, they had multiple! And they often had multiple of the same partition system type. In theory, this could actually disrupt plasmid partition if these systems overlapped!!
December 11, 2025 at 1:30 PM
🧵 3/7 We set out to identify diverse plasmids encoding partition systems and found many plasmids didn’t just have one system, they had multiple! And they often had multiple of the same partition system type. In theory, this could actually disrupt plasmid partition if these systems overlapped!!
🧵 2/7 But what about their distribution across wider bacterial diversity? And how do these systems maintain plasmids in bacteria that do not divide by binary fission, such as Streptomyces, which have a complex filamentous life cycle?
December 11, 2025 at 1:29 PM
🧵 2/7 But what about their distribution across wider bacterial diversity? And how do these systems maintain plasmids in bacteria that do not divide by binary fission, such as Streptomyces, which have a complex filamentous life cycle?
🧵 1/7 Plasmid partition systems segregate plasmid copies during cell division. There are several evolutionarily distinct partition system types and we understand (relatively) well the distribution of these types and how they function in unicellular bacteria, namely in enterobacteria such as E. coli.
December 11, 2025 at 1:28 PM
🧵 1/7 Plasmid partition systems segregate plasmid copies during cell division. There are several evolutionarily distinct partition system types and we understand (relatively) well the distribution of these types and how they function in unicellular bacteria, namely in enterobacteria such as E. coli.