Nucleologenesis and number of ribosomal RNA genes in maize

✍ Scribed by Consuelo Torre; Francisco Colinas

• Publisher: Springer Netherlands
• Year: 1978
• Tongue: English
• Weight: 393 KB
• Volume: 49
• Category: Article
• ISSN: 0016-6707
• DOI: 10.1007/bf00120569

✦ Synopsis

Nucleologenesis has been studied in three Zea mays L. inbred lines (W23, A188 and B37) which posses 5 000, 7 000 and 10 000 rRNA genes per 2C nucleus respectively.

The larger the number of rRNA genes the strain has, the later in the new cycle the fully organized nucleolus is found, and the larger it is. The rate of nucleologenesis apears not to be strictly a linear function of the number of rRNA genes, since this rate is larger in the 5 000 gene line (41 x 10 -s //m 3 h -1 per rRNA gene) than in the other two maize lines.

There is no nucleologenesis if RNA synthesis is inhibited, while by inhibiting protein synthesis the nucleologenesis rate in the 10 000 rRNA gene line (32 x 10 -s grn 3 h -1 per rRNA gene) is raised to 37 x 10 -5 ~tm 3 h q per rRNA gene.

These findings support the hypothesis that nucleologenesis is a primary function linked to the reinitiation of transcription of the rRNA genes present in the reforming nucleus, and can be increased by inhibiting the cell's simultaneous protein synthesis.