Transient concentration of a gamma-tubulin-related protein with a pericentrin-related protein in the formation of basal bodies and flagella during the differentiation of Naegleria gruberi.
The distribution of two proteins in Naegleria gruberi, N-gammaTRP (Naegleria gamma-tubulin-related protein) and N-PRP (Naegleria pericentrin-related protein), was examined during the de novo formation of basal bodies and flagella that occurs during the differentiation of N. gruberi. After the initiation of differentiation, N-gammaTRP and N-PRP began to concentrate at the same site within cells. The percentage of cells with a concentrated region of N-gammaTRP and N-PRP was maximal (68%) at 40 min when the synthesis of tubulin had just started but no assembled microtubules were visible. When concentrated tubulin became visible (60 min), the region of concentrated N-gammaTRP and N-PRP was co-localized with the tubulin spot and then flagella began to elongate from the region of concentrated tubulin. When cells had elongated flagella, the concentrated N-gammaTRP and N-PRP were translocated to the opposite end of the flagellated cells and disappeared. The transient concentration of N-gammaTRP coincided with the transient formation of an F-actin spot at which N-gammaTRP and alpha-tubulin mRNA were co-localized. The concentration of N-gammaTRP and formation of the F-actin spot occurred without the formation of microtubules but were inhibited by cytochalasin D. These observations suggest that the regional concentration of N-gammaTRP and N-PRP is mediated by actin filaments and might provide a site of microtubule nucleation for the assembly of newly synthesized tubulins into basal bodies and flagella.
Department of Biology and Institute of Bioscience and Biotechnology, Yonsei University, Seoul 120-749, Korea.
Mi Ra
MR
Suh
Ji Woong
JW
Han
Yi Ran
YR
No
JooHun
J
Lee
D000199:Actins / Q000378:metabolism; D000818:Animals; D000941:Antigens / Q000032:analysis* / Q000502:physiology; D002454:Cell Differentiation; D002502:Centrioles / Q000737:chemistry*; D015638:Cytochalasin D / Q000378:metabolism; D005407:Flagella / Q000737:chemistry* / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000032:analysis / Q000145:classification; D009253:Naegleria / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D015800:Protozoan Proteins / Q000032:analysis* / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D014404:Tubulin / Q000032:analysis* / Q000737:chemistry / Q000502:physiology
D000199:Actins; D000941:Antigens; D008869:Microtubule-Associated Proteins; D015800:Protozoan Proteins; D012333:RNA, Messenger; D014404:Tubulin; C086178:pericentrin; D015638:Cytochalasin D