Biopolym. Cell. 2019; 35(3):241-242.
Хроника и информация
Organization of zebra finch oocyte nucleus
1Володкина В., 1, 2Сафитдинова А., 1Кулак М., 3Кошель Е., 1Галкина С., 1Гадинская Е.
  1. Saint Petersburg State University
    Saint Petersburg, Russia
  2. Herzen State Pedagogical University of Russia
    Saint Petersburg, Russia
  3. ITMO University
    Saint Petersburg, Russia

Abstract

Transcriptionally active lampbrush chromosomes and numerous of different intranuclear structures make nuclei of birds’ growing oocytes a working model for investigation of nuclear structure and function. Studies of nucleus content were already made for chicken (Gallus gallus), quail (Coturnix japonica), chaffinch (Fringilla coelebs) and rock pigeon (Columbia livia). Here, we examine the organization of zebra finch (Taeniopygia guttata) oocyte nucleus and look at intranuclear structures. Zebra finch is a singing bird of Estrildidae family that belongs to Passeriformes. This bird is a well-known model object of neurobiology. To implement our idea we combine the methods of nuclei isolation, confocal microscopy and immunocytochemistry. We found out that there are a lot of (~ 40) small bodies (less than 0,5 μm) on the nucleus periphery. Intranuclear bodies of 5 μm in size contain RNA (RiboGreen), coilin (R288) and FLASH. They are attached to chromosomes. The presence of coilin suggests these structures are some kind of Cajal bodies. However FLASH protein is a marker of histone locus bodies. At the same time zebra finch oocyte nucleus do not contain ‘protein bodies’ which are common for chaffinch. The lampbrush chromosomes lie in the center of nucleus and do not contact inner nuclear membrane. The most peculiar one is germline-restricted chromosome (GRC) which is the biggest chromosome in karyotype. It is actively transcribed but presents only in gametes. Lampbrush form of this chromosome have obvious condensed ‘belts’. There are small coilin positive bodies attached to this ‘belts’. We see, that even members of the same order but different families have various intranuclear structures. Funding: Research Resource Centre “Chromas” of Saint Petersburg State University.