Prediction of the Coding Sequences of Unidentified Human Genes. IV. The Coding Sequences of 40 New Genes (KIAA0121-KIAA0160) Deduced by Analysis of cDNA Clones from Human Cell Line KG-1

In this series of projects regarding the accumulation of sequenceinformation of unidentified human genes, we newly deduced thesequences of 40 full-length cDNA clones of human cell line KG-1,and predicted the coding sequences of the corresponding genes,named KIAA0121 to 0160. The results of a computer search ofpublic databases indicated that the sequences of 13 genes wereunrelated to any reported genes, while the remaining 27 genescarried sequences which showed some similarities to known genes.Obvious unique sequences noted were as follows. A stretch oftriplet repeats was contained in each of three genes: Thesewere GAG(Glu) in KIAA0122 and KIAA0147, and TCC(Ser) in KIAA0150.A stretch of 10 amino acidresidues was repeated 21 times inKIAA0139, and a homologous sequence of 76–78 nucleotideswas found repeated 6 times in the untranslated region of KIAA0125.northern hybridization analysis demonstrated that 13 genes wereexpressed in a cell- or tissue-specific manner. Although a vastnumber of expressed sequence tags (ESTs) have been registeredfor comprehensive analysis of cDNA clones, our sequence dataindicated that their distribution is very unbalanced: e.g. whileno EST hit 7 genes, 85 ESTs fell in a single gene.     

Prediction of the Coding Sequences of Unidentified Human Genes. III. The Coding Sequences of 40 New Genes (KIAA0081-KIAA0120) Deduced by Analysis of cDNA Clones from Human Cell Line KG-1

We isolated full-length cDNA clones from size-fractionated cDNAlibraries of human immature myeloid cell line KG-1, and thecoding sequences of 40 genes were newly predicted. A computersearch of the GenBank/EMBL databases indicated that the sequencesof 14 genes were unrelated to any reported genes, while theremaining 26 genes carried some sequences with similaritiesto known genes. Significant transmembrane domains were identifiedin 17 genes, and protein motifs that matched those in the PROSITEmotif database were identified in 11 genes. Northern hybridizationanalysis with 18 different cells and tissues demonstrated that10 genes were apparently expressed in a cell-specific or tissue-specificmanner. Among the genes predicted, half were isolated from themedium-sized cDNA library and the other half from the small-sizedcDNA library, and their average sizes were 4 kb and 1.4 kb,respectively. As judged by Northern hybridization profiles,small-sized cDNAs appeared to be expressed more ubiquitouslyand abundantly in various tissues, compared with that of medium-sizedcDNAs.     

Prediction of the coding sequences of mouse homologues of KIAA gene: III. the complete nucleotide sequences of 500 mouse KIAA-homologous cDNAs identified by screening of terminal sequences of cDNA clones randomly sampled from size-fractionated libraries.

We have conducted a human cDNA project to predict protein-coding sequences (CDSs) in large cDNAs (> 4 kb) since 1994, and the number of newly identified genes, known as KIAA genes, already exceeds 2000. The ultimate goal of this project is to clarify the physiological functions of the proteins encoded by KIAA genes. To this end, the project has recently been expanded to include isolation and characterization of mouse KIAA-counterpart genes. We herein present the entire sequences and the chromosome loci of 500 mKIAA cDNA clones and 13 novel cDNA clones that were incidentally identified during this project. The average size of the 513 cDNA sequences reached 4.3 kb and that of the deduced amino acid sequences from these cDNAs was 816 amino acid residues. By comparison of the predicted CDSs between mouse and human KIAAs, 12 mKIAA cDNA clones were assumed to be differently spliced isoforms of the human cDNA clones. The comparison of mouse and human sequences also revealed that four pairs of human KIAA cDNAs are derived from single genes. Notably, a homology search against the public database indicated that 4 out of 13 novel cDNA clones were homologous to the disease-related genes.     

Prediction of the coding sequences of mouse homologues of KIAA gene: IV. The complete nucleotide sequences of 500 mouse KIAA-homologous cDNAs identified by screening of terminal sequences of cDNA clones randomly sampled from size-fractionated libraries.

We have been conducting a mouse cDNA project to predict protein-coding sequences of mouse homologues of human KIAA and FLJ genes since 2001. As an extension of these projects, we herein present the entire sequences of 500 mKIAA cDNA clones and 4 novel cDNA clones that were incidentally identified during this project. We have isolated cDNA clones from the size-fractionated mouse cDNA libraries derived from 7 tissues and 3 types of cultured cells. The average size of the 504 cDNA sequences reached 4.3 kb and that of the deduced amino acid sequences from these cDNAs was 807 amino acid residues. We assigned the integrity of CDSs from the comparison with the corresponding human KIAA cDNA sequences. The comparison of mouse and human sequences revealed that two different human KIAA cDNAs are derived from single genes. Furthermore, 3 out of 4 proteins encoded in the novel cDNA clones showed moderate sequence similarity with human KIAA proteins, thus we could obtain new members of KIAA protein families through our mouse cDNA projects.     

Prediction of the coding sequences of mouse homologues of KIAA gene: II. The complete nucleotide sequences of 400 mouse KIAA-homologous cDNAs identified by screening of terminal sequences of cDNA clones randomly sampled from size-fractionated libraries.

We have accumulated information of the coding sequences of uncharacterized human genes, which are known as KIAA genes, and the number of these genes exceeds 2000 at present. As an extension of this sequencing project, we recently have begun to accumulate mouse KIAA-homologous cDNAs, because it would be useful to prepare a set of human and mouse homologous cDNA pairs for further functional analysis of the KIAA genes. We herein present the entire sequences of 400 mouse KIAA cDNA clones and 4 novel cDNA clones which were incidentally identified during this project. Most of clones entirely sequenced in this study were selected by computer-assisted analysis of terminal sequences of the cDNAs. The average size of the 404 cDNA sequences reached 5.3 kb and that of the deduced amino acid sequences from these cDNAs was 868 amino acid residues. The results of sequence analyses of these clones showed that single mouse KIAA cDNAs bridged two different human KIAA cDNAs in some cases, which indicated that these two human KIAA cDNAs were derived from single genes although they had been supposed to originate from different genes. Furthermore, we successfully mapped all the mouse KIAA cDNAs along the genome using a recently published mouse genome draft sequence.