Pompeo Jennifer Nunes, Gatto Kaleb Pretto, Baldo Diego, Lourenço Luciana Bolsoni
Laboratório de Estudos Cromossômicos, Instituto de Biologia, Universidade de Campinas, Campinas 13083-862, SP, Brazil.
Laboratório de Citogenética Evolutiva e Conservação Animal, Departamento de Genética, Setor de Ciências Biológicas, Universidade Federal do Paraná, Curitiba 81531-980, PR, Brazil.
Genes (Basel). 2024 Dec 5;15(12):1572. doi: 10.3390/genes15121572.
The satellite DNA (satDNA) PcP190 has been identified in multiple frog species from seven phylogenetically distant families within Hyloidea, indicating its broad distribution. This satDNA consists of repeats of approximately 190 bp and exhibits a highly conserved region (CR) of 120 bp, which is similar to the transcribed region of 5S ribosomal DNA (rDNA), and a hypervariable region (HR) that varies in size and nucleotide composition among and within species. Here, to improve our understanding of PcP190 satDNA, we searched for evidence of its transcription in the available transcriptomes of (Bufonidae) and (Leptodactylidae), two phylogenetically distantly related species.
We first characterized the 5S rDNA and PcP190 sequences in these species by searching for them in available genome assemblies. Next, we used the PcP190 (CR and HR) and 5S rDNA sequences of each species as queries to search for these sequences in RNA-seq libraries.
We identified two types of 5S rDNA in each analyzed species, with a new type found in . Our results also revealed a novel type of PcP190 sequence in and a new subtype of PcP-1 in . Transcriptome analyses confirmed the expected transcription of the 5S rRNA gene and showed transcription of both the CR and HR of the PcP190 satDNA in both species and in different tissues.
As the entire repeat of this satDNA is susceptible to transcription, the high variability observed in the HR cannot be attributed to transcriptional activity confined to the CR.
卫星DNA（satDNA）PcP190已在雨蛙超科中7个系统发育关系较远的科的多个蛙类物种中被鉴定出来，这表明其分布广泛。这种satDNA由大约190 bp的重复序列组成，并具有一个120 bp的高度保守区域（CR），该区域与5S核糖体DNA（rDNA）的转录区域相似，还有一个高变区域（HR），其大小和核苷酸组成在物种间和物种内都有所不同。在这里，为了增进我们对PcP190 satDNA的了解，我们在两个系统发育关系较远的物种——蟾蜍科和细趾蟾科——的现有转录组中寻找其转录的证据。
我们首先通过在可用的基因组组装中搜索，对这些物种中的5S rDNA和PcP190序列进行了特征描述。接下来，我们使用每个物种的PcP190（CR和HR）和5S rDNA序列作为查询序列，在RNA-seq文库中搜索这些序列。
我们在每个分析的物种中鉴定出两种类型的5S rDNA，其中在[物种名1]中发现了一种新类型。我们的结果还揭示了在[物种名2]中一种新型的PcP190序列以及在[物种名3]中一种新的PcP - 1亚型。转录组分析证实了5S rRNA基因的预期转录，并显示了PcP190 satDNA的CR和HR在这两个物种的不同组织中均有转录。
由于这种satDNA的整个重复序列都易于转录，因此在HR中观察到的高变异性不能归因于局限于CR的转录活性。
